OMNIA SCIENTIA
OMNIA SCIENTIA
OMNIA SCIENTIA
OMNIA SCIENTIA
OMNIA SCIENTIA
PHYSICS & CHEMISTRY
PHYSICS & CHEMISTRY
PHYSICS & CHEMISTRY
PHYSICS & CHEMISTRY
PHYSICS & CHEMISTRY
INTERNATIONAL UNITS OF SI
INTERNATIONAL UNITS OF SI
INTERNATIONAL UNITS OF SI
INTERNATIONAL UNITS OF SI
INTERNATIONAL UNITS OF SI
7 BASE & 22 DERIVED UNITS
7 BASE & 22 DERIVED UNITS
7 BASE & 22 DERIVED UNITS
7 BASE & 22 DERIVED UNITS
7 BASE & 22 DERIVED UNITS
BASE UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
BASE UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
BASE UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
BASE UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
BASE UNITS  
Ampere 
Ampere, A
SI Base Unit 

Electric Current, I
SI Base Quantity 

This unit of electric current (1 amp) is the flow capacity of the electric charge in one coulomb over a duration of one second. One coulomb is equivalent to the charge of 6.242×10^{18} electrons. Formally, as defined in 2014: “The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular crosssection, and placed 1m apart in vacuum, would produce between these conductors a force equal to 2 × 10^{−7} newton per metre of length.” Proposed: “The ampere, A, is the unit of electric current; its magnitude is set by fixing the numerical value of the elementary charge to be equal to exactly 1.602 17X × 10^{−19} when it is expressed in the unit A·s, which is equal to C.” Discovered by AndréMarie Ampère, 1820 
Ampere 
Ampere, A
SI Base Unit 

Electric Current, I
SI Base Quantity 

This unit of electric current (1 amp) is the flow capacity of the electric charge in one coulomb over a duration of one second. One coulomb is equivalent to the charge of 6.242×10^{18} electrons. Formally, as defined in 2014: “The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular crosssection, and placed 1m apart in vacuum, would produce between these conductors a force equal to 2 × 10^{−7} newton per metre of length.” Proposed: “The ampere, A, is the unit of electric current; its magnitude is set by fixing the numerical value of the elementary charge to be equal to exactly 1.602 17X × 10^{−19} when it is expressed in the unit A·s, which is equal to C.” Discovered by

Ampere 
Ampere, A
SI Base Unit 

Electric Current, I
SI Base Quantity 

This unit of electric current (1 amp) is the flow capacity of the electric charge in one coulomb over a duration of one second. One coulomb is equivalent to the charge of 6.242×10^{18} electrons. Formally, as defined in 2014: “The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular crosssection, and placed 1m apart in vacuum, would produce between these conductors a force equal to 2 × 10^{−7} newton per metre of length.” Proposed: “The ampere, A, is the unit of electric current; its magnitude is set by fixing the numerical value of the elementary charge to be equal to exactly 1.602 17X × 10^{−19} when it is expressed in the unit A·s, which is equal to C.” Discovered by

Ampere 
Ampere, A
SI Base Unit 

Electric Current, I
SI Base Quantity 

This unit of electric current (1 amp) is the flow capacity of the electric charge in one coulomb over a duration of one second. One coulomb is equivalent to the charge of 6.242×10^{18} electrons. Formally, as defined in 2014: “The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular crosssection, and placed 1m apart in vacuum, would produce between these conductors a force equal to 2 × 10^{−7} newton per metre of length.” Proposed: “The ampere, A, is the unit of electric current; its magnitude is set by fixing the numerical value of the elementary charge to be equal to exactly 1.602 17X × 10^{−19} when it is expressed in the unit A·s, which is equal to C.” Discovered by

Ampere 
Ampere, A
SI Base Unit 

Electric Current, I
SI Base Quantity 

This unit of electric current (1 amp) is the flow capacity of the electric charge in one coulomb over a duration of one second. One coulomb is equivalent to the charge of 6.242×10^{18} electrons. Formally, as defined in 2014: “The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular crosssection, and placed 1m apart in vacuum, would produce between these conductors a force equal to 2 × 10^{−7} newton per metre of length.” Proposed: “The ampere, A, is the unit of electric current; its magnitude is set by fixing the numerical value of the elementary charge to be equal to exactly 1.602 17X × 10^{−19} when it is expressed in the unit A·s, which is equal to C.” Discovered by

Candela 
Candela, cd
SI Base Unit 

Luminous Intensity, J
SI Base Quantity 

This unit is based on a common candle emitting light with a luminous intensity of one candela. The amount of light illuminating a surface area is called the illuminance and is measured in lumens: 1 lumen = 1 candela x steradian. The energy of 1 candle (candela) passing through a spherical 360 degree surface area with a 1 metre radius, will give a sphere surface area of 4 pi r^{2} = 12.57 m^{2} = 12.57 lumens. With an apex angle of 360°: 1 candela = 12.57 lumen, 1 lumen = 0.08 candela. With a surface area of 12.57m^{2}: 1 lumen = 0.08 lux, 1 lux = 12.57 lumen. At a distance of 1m: 1 candela = 1 lux, 1 lux = 1 candela. Formally, as defined in 2014: “The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 10^{12} Hz and that has a radiant intensity in that direction of 1/683 watt per steradian” Proposed: “The candela, cd, is the unit of luminous intensity in a given direction; its magnitude is set by fixing the numerical value of the luminous efficacy of monochromatic radiation of frequency 540 × 10^{12} Hz to be equal to exactly 683 when it is expressed in the unit s^{3}·m^{2}·kg^{1}·cd·sr, or cd·sr·W^{1}, which is equal to lm·W^{1}.” Discovered by Jules Louis Gabriel Violle, 1881 
Candela 
Candela, cd
SI Base Unit 

Luminous Intensity, J
SI Base Quantity 

This unit is based on a common candle emitting light with a luminous intensity of one candela. The amount of light illuminating a surface area is called the illuminance and is measured in lumens: 1 lumen = 1 candela x steradian. The energy of 1 candle (candela) passing through a spherical 360 degree surface area with a 1 metre radius, will give a sphere surface area of 4 pi r^{2} = 12.57 m^{2} = 12.57 lumens. With an apex angle of 360°: 1 candela = 12.57 lumen, 1 lumen = 0.08 candela. With a surface area of 12.57m^{2}: 1 lumen = 0.08 lux, 1 lux = 12.57 lumen. At a distance of 1m: 1 candela = 1 lux, 1 lux = 1 candela. Formally, as defined in 2014: “The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 10^{12} Hz and that has a radiant intensity in that direction of 1/683 watt per steradian” Proposed: “The candela, cd, is the unit of luminous intensity in a given direction; its magnitude is set by fixing the numerical value of the luminous efficacy of monochromatic radiation of frequency 540 × 10^{12} Hz to be equal to exactly 683 when it is expressed in the unit s^{3}·m^{2}·kg^{1}·cd·sr, or cd·sr·W^{1}, which is equal to lm·W^{1}.” Discovered by

Candela 
Candela, cd
SI Base Unit 

Luminous Intensity, J
SI Base Quantity 

This unit is based on a common candle emitting light with a luminous intensity of one candela. The amount of light illuminating a surface area is called the illuminance and is measured in lumens: 1 lumen = 1 candela x steradian. The energy of 1 candle (candela) passing through a spherical 360 degree surface area with a 1 metre radius, will give a sphere surface area of 4 pi r^{2} = 12.57 m^{2} = 12.57 lumens. With an apex angle of 360°: 1 candela = 12.57 lumen, 1 lumen = 0.08 candela. With a surface area of 12.57m^{2}: 1 lumen = 0.08 lux, 1 lux = 12.57 lumen. At a distance of 1m: 1 candela = 1 lux, 1 lux = 1 candela. Formally, as defined in 2014: “The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 10^{12} Hz and that has a radiant intensity in that direction of 1/683 watt per steradian” Proposed: “The candela, cd, is the unit of luminous intensity in a given direction; its magnitude is set by fixing the numerical value of the luminous efficacy of monochromatic radiation of frequency 540 × 10^{12} Hz to be equal to exactly 683 when it is expressed in the unit s^{3}·m^{2}·kg^{1}·cd·sr, or cd·sr·W^{1}, which is equal to lm·W^{1}.” Discovered by

Candela 
Candela, cd
SI Base Unit 

Luminous Intensity, J
SI Base Quantity 

This unit is based on a common candle emitting light with a luminous intensity of one candela. The amount of light illuminating a surface area is called the illuminance and is measured in lumens: 1 lumen = 1 candela x steradian. The energy of 1 candle (candela) passing through a spherical 360 degree surface area with a 1 metre radius, will give a sphere surface area of 4 pi r^{2} = 12.57 m^{2} = 12.57 lumens. With an apex angle of 360°: 1 candela = 12.57 lumen, 1 lumen = 0.08 candela. With a surface area of 12.57m^{2}: 1 lumen = 0.08 lux, 1 lux = 12.57 lumen. At a distance of 1m: 1 candela = 1 lux, 1 lux = 1 candela. Formally, as defined in 2014: “The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 10^{12} Hz and that has a radiant intensity in that direction of 1/683 watt per steradian” Proposed: “The candela, cd, is the unit of luminous intensity in a given direction; its magnitude is set by fixing the numerical value of the luminous efficacy of monochromatic radiation of frequency 540 × 10^{12} Hz to be equal to exactly 683 when it is expressed in the unit s^{3}·m^{2}·kg^{1}·cd·sr, or cd·sr·W^{1}, which is equal to lm·W^{1}.” Discovered by

Candela 
Candela, cd
SI Base Unit 

Luminous Intensity, J
SI Base Quantity 

This unit is based on a common candle emitting light with a luminous intensity of one candela. The amount of light illuminating a surface area is called the illuminance and is measured in lumens: 1 lumen = 1 candela x steradian. The energy of 1 candle (candela) passing through a spherical 360 degree surface area with a 1 metre radius, will give a sphere surface area of 4 pi r^{2} = 12.57 m^{2} = 12.57 lumens. With an apex angle of 360°: 1 candela = 12.57 lumen, 1 lumen = 0.08 candela. With a surface area of 12.57m^{2}: 1 lumen = 0.08 lux, 1 lux = 12.57 lumen. At a distance of 1m: 1 candela = 1 lux, 1 lux = 1 candela. Formally, as defined in 2014: “The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 10^{12} Hz and that has a radiant intensity in that direction of 1/683 watt per steradian” Proposed: “The candela, cd, is the unit of luminous intensity in a given direction; its magnitude is set by fixing the numerical value of the luminous efficacy of monochromatic radiation of frequency 540 × 10^{12} Hz to be equal to exactly 683 when it is expressed in the unit s^{3}·m^{2}·kg^{1}·cd·sr, or cd·sr·W^{1}, which is equal to lm·W^{1}.” Discovered by

Kelvin 
Kelvin, K
SI Base Unit 

Temperature, Θ
SI Base Quantity 

The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics. The kelvin is defined as the fraction 1⁄273.16 of the thermodynamic temperature of the triple point of water (exactly 0.01 °C or 32.018 °F). The triple point of water is exactly 273.16 K. Formally, as defined in 2014: “The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.” Proposed: “The kelvin, K, is the unit of thermodynamic temperature; its magnitude is set by fixing the numerical value of the Boltzmann constant to be equal to exactly 1.380 65X × 10^{−23} when it is expressed in the unit s^{−2}·m^{2}·kg·K^{−1}, which is equal to J·K^{−1}.” Discovered by Lord William Kelvin, 1848 
Kelvin 
Kelvin, K
SI Base Unit 

Temperature, Θ
SI Base Quantity 

The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics. The kelvin is defined as the fraction 1⁄273.16 of the thermodynamic temperature of the triple point of water (exactly 0.01 °C or 32.018 °F). The triple point of water is exactly 273.16 K. Formally, as defined in 2014: “The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.” Proposed: “The kelvin, K, is the unit of thermodynamic temperature; its magnitude is set by fixing the numerical value of the Boltzmann constant to be equal to exactly 1.380 65X × 10^{−23} when it is expressed in the unit s^{−2}·m^{2}·kg·K^{−1}, which is equal to J·K^{−1}.” Discovered by

Kelvin 
Kelvin, K
SI Base Unit 

Temperature, Θ
SI Base Quantity 

The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics. The kelvin is defined as the fraction 1⁄273.16 of the thermodynamic temperature of the triple point of water (exactly 0.01 °C or 32.018 °F). The triple point of water is exactly 273.16 K. Formally, as defined in 2014: “The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.” Proposed: “The kelvin, K, is the unit of thermodynamic temperature; its magnitude is set by fixing the numerical value of the Boltzmann constant to be equal to exactly 1.380 65X × 10^{−23} when it is expressed in the unit s^{−2}·m^{2}·kg·K^{−1}, which is equal to J·K^{−1}.” Discovered by

Kelvin 
Kelvin, K
SI Base Unit 

Temperature, Θ
SI Base Quantity 

The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics. The kelvin is defined as the fraction 1⁄273.16 of the thermodynamic temperature of the triple point of water (exactly 0.01 °C or 32.018 °F). The triple point of water is exactly 273.16 K. Formally, as defined in 2014: “The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.” Proposed: “The kelvin, K, is the unit of thermodynamic temperature; its magnitude is set by fixing the numerical value of the Boltzmann constant to be equal to exactly 1.380 65X × 10^{−23} when it is expressed in the unit s^{−2}·m^{2}·kg·K^{−1}, which is equal to J·K^{−1}.” Discovered by

Kelvin 
Kelvin, K
SI Base Unit 

Temperature, Θ
SI Base Quantity 

The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics. The kelvin is defined as the fraction 1⁄273.16 of the thermodynamic temperature of the triple point of water (exactly 0.01 °C or 32.018 °F). The triple point of water is exactly 273.16 K. Formally, as defined in 2014: “The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.” Proposed: “The kelvin, K, is the unit of thermodynamic temperature; its magnitude is set by fixing the numerical value of the Boltzmann constant to be equal to exactly 1.380 65X × 10^{−23} when it is expressed in the unit s^{−2}·m^{2}·kg·K^{−1}, which is equal to J·K^{−1}.” Discovered by

Kilogram 
Kilogram, kg
SI Base Unit 

Mass, M
SI Base Quantity 

The gram, 1/1000th of a kilogram, was originally defined as the mass of one cubic centimetre of water at the melting point of water. The original prototype kilogram, manufactured in 1799, has a mass equal to the mass of 1.000’028 dm^{3} of water at its maximum density at approximately 4 °C. The kilogram is the only SI base unit with a prefix (kilo) as part of its name and directly defined by an artefact rather than a fundamental physical property. Three SI Base units (Cd, A, mol) and 17 SI Derived units (N, Pa, J, W, C, V, F, Ω, S, Wb, T, H, kat, Gy, Sv, lm, lx) are defined relative to the kilogram. Only 8 SI units do not require the kilogram in their definition: temperature (K, °C), time and frequency (s, Hz, Bq), length (m), and angle (rad, sr). The International Committee for Weights and Measures have undertaken to redefine the kilogram in terms of a fundamental constant of nature, as in the Planck constant. Formally, as defined in 2014: “The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.” Proposed: “The kilogram, kg, is the unit of mass; its magnitude is set by fixing the numerical value of the Planck constant to be equal to exactly 6.626 06X × 10^{−34} when it is expressed in the unit s^{−1}·m^{2}·kg, which is equal to J·s.” 
Kilogram 
Kilogram, kg
SI Base Unit 

Mass, M
SI Base Quantity 

The gram, 1/1000th of a kilogram, was originally defined as the mass of one cubic centimetre of water at the melting point of water. The original prototype kilogram, manufactured in 1799, has a mass equal to the mass of 1.000’028 dm^{3} of water at its maximum density at approximately 4 °C. The kilogram is the only SI base unit with a prefix (kilo) as part of its name and directly defined by an artefact rather than a fundamental physical property. Three SI Base units (Cd, A, mol) and 17 SI Derived units (N, Pa, J, W, C, V, F, Ω, S, Wb, T, H, kat, Gy, Sv, lm, lx) are defined relative to the kilogram. Only 8 SI units do not require the kilogram in their definition: temperature (K, °C), time and frequency (s, Hz, Bq), length (m), and angle (rad, sr). The International Committee for Weights and Measures have undertaken to redefine the kilogram in terms of a fundamental constant of nature, as in the Planck constant. Formally, as defined in 2014: “The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.” Proposed: “The kilogram, kg, is the unit of mass; its magnitude is set by fixing the numerical value of the Planck constant to be equal to exactly 6.626 06X × 10^{−34} when it is expressed in the unit s^{−1}·m^{2}·kg, which is equal to J·s.” 
Kilogram 
Kilogram, kg
SI Base Unit 

Mass, M
SI Base Quantity 

The gram, 1/1000th of a kilogram, was originally defined as the mass of one cubic centimetre of water at the melting point of water. The original prototype kilogram, manufactured in 1799, has a mass equal to the mass of 1.000’028 dm^{3} of water at its maximum density at approximately 4 °C. The kilogram is the only SI base unit with a prefix (kilo) as part of its name and directly defined by an artefact rather than a fundamental physical property. Three SI Base units (Cd, A, mol) and 17 SI Derived units (N, Pa, J, W, C, V, F, Ω, S, Wb, T, H, kat, Gy, Sv, lm, lx) are defined relative to the kilogram. Only 8 SI units do not require the kilogram in their definition: temperature (K, °C), time and frequency (s, Hz, Bq), length (m), and angle (rad, sr). The International Committee for Weights and Measures have undertaken to redefine the kilogram in terms of a fundamental constant of nature, as in the Planck constant. Formally, as defined in 2014: “The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.” Proposed: “The kilogram, kg, is the unit of mass; its magnitude is set by fixing the numerical value of the Planck constant to be equal to exactly 6.626 06X × 10^{−34} when it is expressed in the unit s^{−1}·m^{2}·kg, which is equal to J·s.” 
Kilogram 
Kilogram, kg
SI Base Unit 

Mass, M
SI Base Quantity 

The gram, 1/1000th of a kilogram, was originally defined as the mass of one cubic centimetre of water at the melting point of water. The original prototype kilogram, manufactured in 1799, has a mass equal to the mass of 1.000’028 dm^{3} of water at its maximum density at approximately 4 °C. The kilogram is the only SI base unit with a prefix (kilo) as part of its name and directly defined by an artefact rather than a fundamental physical property. Three SI Base units (Cd, A, mol) and 17 SI Derived units (N, Pa, J, W, C, V, F, Ω, S, Wb, T, H, kat, Gy, Sv, lm, lx) are defined relative to the kilogram. Only 8 SI units do not require the kilogram in their definition: temperature (K, °C), time and frequency (s, Hz, Bq), length (m), and angle (rad, sr). The International Committee for Weights and Measures have undertaken to redefine the kilogram in terms of a fundamental constant of nature, as in the Planck constant. Formally, as defined in 2014: “The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.” Proposed: “The kilogram, kg, is the unit of mass; its magnitude is set by fixing the numerical value of the Planck constant to be equal to exactly 6.626 06X × 10^{−34} when it is expressed in the unit s^{−1}·m^{2}·kg, which is equal to J·s.” 
Kilogram 
Kilogram, kg
SI Base Unit 

Mass, M
SI Base Quantity 

The gram, 1/1000th of a kilogram, was originally defined as the mass of one cubic centimetre of water at the melting point of water. The original prototype kilogram, manufactured in 1799, has a mass equal to the mass of 1.000’028 dm^{3} of water at its maximum density at approximately 4 °C. The kilogram is the only SI base unit with a prefix (kilo) as part of its name and directly defined by an artefact rather than a fundamental physical property. Three SI Base units (Cd, A, mol) and 17 SI Derived units (N, Pa, J, W, C, V, F, Ω, S, Wb, T, H, kat, Gy, Sv, lm, lx) are defined relative to the kilogram. Only 8 SI units do not require the kilogram in their definition: temperature (K, °C), time and frequency (s, Hz, Bq), length (m), and angle (rad, sr). The International Committee for Weights and Measures have undertaken to redefine the kilogram in terms of a fundamental constant of nature, as in the Planck constant. Formally, as defined in 2014: “The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.” Proposed: “The kilogram, kg, is the unit of mass; its magnitude is set by fixing the numerical value of the Planck constant to be equal to exactly 6.626 06X × 10^{−34} when it is expressed in the unit s^{−1}·m^{2}·kg, which is equal to J·s.” 
Metre 
Metre, m
SI Base Unit 

Length, L
SI Base Quantity 

Originally defined as one tenmillionth of the distance from the equator to the North Pole. In 1889, it was redefined in terms of a prototype metre bar then in 1960, the metre was redefined as equal to 1 650 763.73 wavelengths of the orangered emission line in the electromagnetic spectrum of the krypton86 atom in a vacuum. The metre is now defined as the path length travelled by light in a given time with practical laboratory length measurements, in metres, determined by counting the number of wavelengths of laser light and converting the selected unit of wavelength to metres. Three major factors limit this accuracy for length measurement: Uncertainty in vacuum wavelength of the source, refractive index of the medium and count resolution of the interferometer. Formally, as defined in 2014: “The metre is the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second.” Proposed: “The metre, m, is the unit of length; its magnitude is set by fixing the numerical value of the speed of light in vacuum to be equal to exactly 299,792,458 when it is expressed in the unit m·s^{−1}.” 
Metre 
Metre, m
SI Base Unit 

Length, L
SI Base Quantity 

Originally defined as one tenmillionth of the distance from the equator to the North Pole. In 1889, it was redefined in terms of a prototype metre bar then in 1960, the metre was redefined as equal to 1 650 763.73 wavelengths of the orangered emission line in the electromagnetic spectrum of the krypton86 atom in a vacuum. The metre is now defined as the path length travelled by light in a given time with practical laboratory length measurements, in metres, determined by counting the number of wavelengths of laser light and converting the selected unit of wavelength to metres. Three major factors limit this accuracy for length measurement: Uncertainty in vacuum wavelength of the source, refractive index of the medium and count resolution of the interferometer. Formally, as defined in 2014: “The metre is the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second.” Proposed: “The metre, m, is the unit of length; its magnitude is set by fixing the numerical value of the speed of light in vacuum to be equal to exactly 299,792,458 when it is expressed in the unit m·s^{−1}.” 
Metre 
Metre, m
SI Base Unit 

Length, L
SI Base Quantity 

Originally defined as one tenmillionth of the distance from the equator to the North Pole. In 1889, it was redefined in terms of a prototype metre bar then in 1960, the metre was redefined as equal to 1 650 763.73 wavelengths of the orangered emission line in the electromagnetic spectrum of the krypton86 atom in a vacuum. The metre is now defined as the path length travelled by light in a given time with practical laboratory length measurements, in metres, determined by counting the number of wavelengths of laser light and converting the selected unit of wavelength to metres. Three major factors limit this accuracy for length measurement: Uncertainty in vacuum wavelength of the source, refractive index of the medium and count resolution of the interferometer. Formally, as defined in 2014: “The metre is the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second.” Proposed: “The metre, m, is the unit of length; its magnitude is set by fixing the numerical value of the speed of light in vacuum to be equal to exactly 299,792,458 when it is expressed in the unit m·s^{−1}.” 
Metre 
Metre, m
SI Base Unit 

Length, L
SI Base Quantity 

Originally defined as one tenmillionth of the distance from the equator to the North Pole. In 1889, it was redefined in terms of a prototype metre bar then in 1960, the metre was redefined as equal to 1 650 763.73 wavelengths of the orangered emission line in the electromagnetic spectrum of the krypton86 atom in a vacuum. The metre is now defined as the path length travelled by light in a given time with practical laboratory length measurements, in metres, determined by counting the number of wavelengths of laser light and converting the selected unit of wavelength to metres. Three major factors limit this accuracy for length measurement: Uncertainty in vacuum wavelength of the source, refractive index of the medium and count resolution of the interferometer. Formally, as defined in 2014: “The metre is the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second.” Proposed: “The metre, m, is the unit of length; its magnitude is set by fixing the numerical value of the speed of light in vacuum to be equal to exactly 299,792,458 when it is expressed in the unit m·s^{−1}.” 
Metre 
Metre, m
SI Base Unit 

Length, L
SI Base Quantity 

Originally defined as one tenmillionth of the distance from the equator to the North Pole. In 1889, it was redefined in terms of a prototype metre bar then in 1960, the metre was redefined as equal to 1 650 763.73 wavelengths of the orangered emission line in the electromagnetic spectrum of the krypton86 atom in a vacuum. The metre is now defined as the path length travelled by light in a given time with practical laboratory length measurements, in metres, determined by counting the number of wavelengths of laser light and converting the selected unit of wavelength to metres. Three major factors limit this accuracy for length measurement: Uncertainty in vacuum wavelength of the source, refractive index of the medium and count resolution of the interferometer. Formally, as defined in 2014: “The metre is the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second.” Proposed: “The metre, m, is the unit of length; its magnitude is set by fixing the numerical value of the speed of light in vacuum to be equal to exactly 299,792,458 when it is expressed in the unit m·s^{−1}.” 
Mole 
Mole, mol
SI Base Unit 

Amount of Substance, N
SI Base Quantity 

The mass per mole of a substance is called its molar mass and is measured in grams per mole, exactly equal to its mean molecular or atomic mass, that is measured in unified atomic mass units. The number of elementary entities in a sample of a substance is technically called its (chemical) amount, the unit for that physical quantity, the mole and can be determined by dividing the mass of the sample by the molar mass of the substance. Formally, as defined in 2014: “The mole is the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.” Proposed: “The mole, mol, is the unit of amount of substance of a specified elementary entity, which may be an atom, molecule, ion, electron, any other particle or a specified group of such particles; its magnitude is set by fixing the numerical value of the Avogadro constant to be equal to exactly 6.022 14X × 10^{23} when it is expressed in the unit mol^{−1}.” 
Mole 
Mole, mol
SI Base Unit 

Amount of Substance, N
SI Base Quantity 

The mass per mole of a substance is called its molar mass and is measured in grams per mole, exactly equal to its mean molecular or atomic mass, that is measured in unified atomic mass units. The number of elementary entities in a sample of a substance is technically called its (chemical) amount, the unit for that physical quantity, the mole and can be determined by dividing the mass of the sample by the molar mass of the substance. Formally, as defined in 2014: “The mole is the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.” Proposed: “The mole, mol, is the unit of amount of substance of a specified elementary entity, which may be an atom, molecule, ion, electron, any other particle or a specified group of such particles; its magnitude is set by fixing the numerical value of the Avogadro constant to be equal to exactly 6.022 14X × 10^{23} when it is expressed in the unit mol^{−1}.” 
Mole 
Mole, mol
SI Base Unit 

Amount of Substance, N
SI Base Quantity 

The mass per mole of a substance is called its molar mass and is measured in grams per mole, exactly equal to its mean molecular or atomic mass, that is measured in unified atomic mass units. The number of elementary entities in a sample of a substance is technically called its (chemical) amount, the unit for that physical quantity, the mole and can be determined by dividing the mass of the sample by the molar mass of the substance. Formally, as defined in 2014: “The mole is the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.” Proposed: “The mole, mol, is the unit of amount of substance of a specified elementary entity, which may be an atom, molecule, ion, electron, any other particle or a specified group of such particles; its magnitude is set by fixing the numerical value of the Avogadro constant to be equal to exactly 6.022 14X × 10^{23} when it is expressed in the unit mol^{−1}.” 
Mole 
Mole, mol
SI Base Unit 

Amount of Substance, N
SI Base Quantity 

The mass per mole of a substance is called its molar mass and is measured in grams per mole, exactly equal to its mean molecular or atomic mass, that is measured in unified atomic mass units. The number of elementary entities in a sample of a substance is technically called its (chemical) amount, the unit for that physical quantity, the mole and can be determined by dividing the mass of the sample by the molar mass of the substance. Formally, as defined in 2014: “The mole is the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.” Proposed: “The mole, mol, is the unit of amount of substance of a specified elementary entity, which may be an atom, molecule, ion, electron, any other particle or a specified group of such particles; its magnitude is set by fixing the numerical value of the Avogadro constant to be equal to exactly 6.022 14X × 10^{23} when it is expressed in the unit mol^{−1}.” 
Mole 
Mole, mol
SI Base Unit 

Amount of Substance, N
SI Base Quantity 

The mass per mole of a substance is called its molar mass and is measured in grams per mole, exactly equal to its mean molecular or atomic mass, that is measured in unified atomic mass units. The number of elementary entities in a sample of a substance is technically called its (chemical) amount, the unit for that physical quantity, the mole and can be determined by dividing the mass of the sample by the molar mass of the substance. Formally, as defined in 2014: “The mole is the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.” Proposed: “The mole, mol, is the unit of amount of substance of a specified elementary entity, which may be an atom, molecule, ion, electron, any other particle or a specified group of such particles; its magnitude is set by fixing the numerical value of the Avogadro constant to be equal to exactly 6.022 14X × 10^{23} when it is expressed in the unit mol^{−1}.” 
Second 
Second, s
SI Base Unit 

Time, T
SI Base Quantity 

Time divisions began with the earliest civilizations with night and day, then recorded in 2000 BC day and night became twelve hours each. Then after 300 BC, the Babylonians subdivided the day using the sexagesimal system and divided each subsequent subdivision by sixty, then to at least six places after the sexagesimal point, a precision equivalent to 2 microseconds. The first use of the second was in 1000 AD by a Persian scholar AlBiruni and defined the division of time between new moons of certain specific weeks as a number of days, hours, minutes, seconds, thirds, and fourths after noon Sunday. The modern second is subdivided using decimals and the earliest clocks to display seconds appeared post 1560 AD on an unsigned clock depicting Orpheus in the Fremersdorf collection. In 1644 AD, Marin Mersenne, calculated that a pendulum with a length of 39.1 inches (0.994 m) would have a period at one standard gravity of precisely two seconds, one second for a swing forward and one second for the return swing, enabling a pendulum to tick in precise seconds. In 1832, mathematician and physicist, Johann Carl Friedrich Gauss proposed using the second as the base unit of time in his millimetremilligramsecond system of units, defining the second as 1⁄86,400 of a mean solar day. In 1956, the second was redefined in terms of a year (the period of the Earth’s revolution around the Sun) for a particular epoch, described in Newcomb’s Tables of the Sun (1895), which provided a formula for estimating the motion of the Sun relative to the epoch 1900 based on astronomical observations made between 1750 and 1892. In 1960, the second was defined as 1⁄31,556,925.974’7 of the tropical year for 1900 January 0 at 12hour ephemeris time, abandoning any explicit relationship between the scientific second and the length of a day. Formally, as defined in 2014: “The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium133 atom.” Proposed: “The second, s, is the unit of time; its magnitude is set by fixing the numerical value of the ground state hyperfine splitting frequency of the caesium133 atom, at rest and at a temperature of 0 K, to be equal to exactly 9,192,631,770 when it is expressed in the unit s−1, which is equal to Hz.” Invented by Claudius Ptolemy, 150 AD 
Second 
Second, s
SI Base Unit 

Time, T
SI Base Quantity 

Time divisions began with the earliest civilizations with night and day, then recorded in 2000 BC day and night became twelve hours each. Then after 300 BC, the Babylonians subdivided the day using the sexagesimal system and divided each subsequent subdivision by sixty, then to at least six places after the sexagesimal point, a precision equivalent to 2 microseconds. The first use of the second was in 1000 AD by a Persian scholar AlBiruni and defined the division of time between new moons of certain specific weeks as a number of days, hours, minutes, seconds, thirds, and fourths after noon Sunday. The modern second is subdivided using decimals and the earliest clocks to display seconds appeared post 1560 AD on an unsigned clock depicting Orpheus in the Fremersdorf collection. In 1644 AD, Marin Mersenne, calculated that a pendulum with a length of 39.1 inches (0.994 m) would have a period at one standard gravity of precisely two seconds, one second for a swing forward and one second for the return swing, enabling a pendulum to tick in precise seconds. In 1832, mathematician and physicist, Johann Carl Friedrich Gauss proposed using the second as the base unit of time in his millimetremilligramsecond system of units, defining the second as 1⁄86,400 of a mean solar day. In 1956, the second was redefined in terms of a year (the period of the Earth’s revolution around the Sun) for a particular epoch, described in Newcomb’s Tables of the Sun (1895), which provided a formula for estimating the motion of the Sun relative to the epoch 1900 based on astronomical observations made between 1750 and 1892. In 1960, the second was defined as 1⁄31,556,925.974’7 of the tropical year for 1900 January 0 at 12hour ephemeris time, abandoning any explicit relationship between the scientific second and the length of a day. Formally, as defined in 2014: “The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium133 atom.” Proposed: “The second, s, is the unit of time; its magnitude is set by fixing the numerical value of the ground state hyperfine splitting frequency of the caesium133 atom, at rest and at a temperature of 0 K, to be equal to exactly 9,192,631,770 when it is expressed in the unit s−1, which is equal to Hz.” Invented by

Second 
Second, s
SI Base Unit 

Time, T
SI Base Quantity 

Time divisions began with the earliest civilizations with night and day, then recorded in 2000 BC day and night became twelve hours each. Then after 300 BC, the Babylonians subdivided the day using the sexagesimal system and divided each subsequent subdivision by sixty, then to at least six places after the sexagesimal point, a precision equivalent to 2 microseconds. The first use of the second was in 1000 AD by a Persian scholar AlBiruni and defined the division of time between new moons of certain specific weeks as a number of days, hours, minutes, seconds, thirds, and fourths after noon Sunday. The modern second is subdivided using decimals and the earliest clocks to display seconds appeared post 1560 AD on an unsigned clock depicting Orpheus in the Fremersdorf collection. In 1644 AD, Marin Mersenne, calculated that a pendulum with a length of 39.1 inches (0.994 m) would have a period at one standard gravity of precisely two seconds, one second for a swing forward and one second for the return swing, enabling a pendulum to tick in precise seconds. In 1832, mathematician and physicist, Johann Carl Friedrich Gauss proposed using the second as the base unit of time in his millimetremilligramsecond system of units, defining the second as 1⁄86,400 of a mean solar day. In 1956, the second was redefined in terms of a year (the period of the Earth’s revolution around the Sun) for a particular epoch, described in Newcomb’s Tables of the Sun (1895), which provided a formula for estimating the motion of the Sun relative to the epoch 1900 based on astronomical observations made between 1750 and 1892. In 1960, the second was defined as 1⁄31,556,925.974’7 of the tropical year for 1900 January 0 at 12hour ephemeris time, abandoning any explicit relationship between the scientific second and the length of a day. Formally, as defined in 2014: “The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium133 atom.” Proposed: “The second, s, is the unit of time; its magnitude is set by fixing the numerical value of the ground state hyperfine splitting frequency of the caesium133 atom, at rest and at a temperature of 0 K, to be equal to exactly 9,192,631,770 when it is expressed in the unit s−1, which is equal to Hz.” Invented by

Second 
Second, s
SI Base Unit 

Time, T
SI Base Quantity 

Time divisions began with the earliest civilizations with night and day, then recorded in 2000 BC day and night became twelve hours each. Then after 300 BC, the Babylonians subdivided the day using the sexagesimal system and divided each subsequent subdivision by sixty, then to at least six places after the sexagesimal point, a precision equivalent to 2 microseconds. The first use of the second was in 1000 AD by a Persian scholar AlBiruni and defined the division of time between new moons of certain specific weeks as a number of days, hours, minutes, seconds, thirds, and fourths after noon Sunday. The modern second is subdivided using decimals and the earliest clocks to display seconds appeared post 1560 AD on an unsigned clock depicting Orpheus in the Fremersdorf collection. In 1644 AD, Marin Mersenne, calculated that a pendulum with a length of 39.1 inches (0.994 m) would have a period at one standard gravity of precisely two seconds, one second for a swing forward and one second for the return swing, enabling a pendulum to tick in precise seconds. In 1832, mathematician and physicist, Johann Carl Friedrich Gauss proposed using the second as the base unit of time in his millimetremilligramsecond system of units, defining the second as 1⁄86,400 of a mean solar day. In 1956, the second was redefined in terms of a year (the period of the Earth’s revolution around the Sun) for a particular epoch, described in Newcomb’s Tables of the Sun (1895), which provided a formula for estimating the motion of the Sun relative to the epoch 1900 based on astronomical observations made between 1750 and 1892. In 1960, the second was defined as 1⁄31,556,925.974’7 of the tropical year for 1900 January 0 at 12hour ephemeris time, abandoning any explicit relationship between the scientific second and the length of a day. Formally, as defined in 2014: “The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium133 atom.” Proposed: “The second, s, is the unit of time; its magnitude is set by fixing the numerical value of the ground state hyperfine splitting frequency of the caesium133 atom, at rest and at a temperature of 0 K, to be equal to exactly 9,192,631,770 when it is expressed in the unit s−1, which is equal to Hz.” Invented by

Second 
Second, s
SI Base Unit 

Time, T
SI Base Quantity 

Time divisions began with the earliest civilizations with night and day, then recorded in 2000 BC day and night became twelve hours each. Then after 300 BC, the Babylonians subdivided the day using the sexagesimal system and divided each subsequent subdivision by sixty, then to at least six places after the sexagesimal point, a precision equivalent to 2 microseconds. The first use of the second was in 1000 AD by a Persian scholar AlBiruni and defined the division of time between new moons of certain specific weeks as a number of days, hours, minutes, seconds, thirds, and fourths after noon Sunday. The modern second is subdivided using decimals and the earliest clocks to display seconds appeared post 1560 AD on an unsigned clock depicting Orpheus in the Fremersdorf collection. In 1644 AD, Marin Mersenne, calculated that a pendulum with a length of 39.1 inches (0.994 m) would have a period at one standard gravity of precisely two seconds, one second for a swing forward and one second for the return swing, enabling a pendulum to tick in precise seconds. In 1832, mathematician and physicist, Johann Carl Friedrich Gauss proposed using the second as the base unit of time in his millimetremilligramsecond system of units, defining the second as 1⁄86,400 of a mean solar day. In 1956, the second was redefined in terms of a year (the period of the Earth’s revolution around the Sun) for a particular epoch, described in Newcomb’s Tables of the Sun (1895), which provided a formula for estimating the motion of the Sun relative to the epoch 1900 based on astronomical observations made between 1750 and 1892. In 1960, the second was defined as 1⁄31,556,925.974’7 of the tropical year for 1900 January 0 at 12hour ephemeris time, abandoning any explicit relationship between the scientific second and the length of a day. Formally, as defined in 2014: “The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium133 atom.” Proposed: “The second, s, is the unit of time; its magnitude is set by fixing the numerical value of the ground state hyperfine splitting frequency of the caesium133 atom, at rest and at a temperature of 0 K, to be equal to exactly 9,192,631,770 when it is expressed in the unit s−1, which is equal to Hz.” Invented by

DERIVED UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
DERIVED UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
DERIVED UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
DERIVED UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
DERIVED UNITS  
Becquerel 
Becquerel, Bq
SI Derived Unit 

Activity re Radionuclide
SI Derived Quantity 

s^{1}
SI Base Expression 

This unit is defined as the activity of a quantity of radioactive material in which one nucleus decays per second and is equivalent to an inverse second, s^{−1}.Named after Antoine Henri Becquerel 
Becquerel 
Becquerel, Bq
SI Derived Unit 

Activity re Radionuclide
SI Derived Quantity 

s^{1}
SI Base Expression 

This unit is defined as the activity of a quantity of radioactive material in which one nucleus decays per second and is equivalent to an inverse second, s^{−1}.Named after

Becquerel 
Becquerel, Bq
SI Derived Unit 

Activity re Radionuclide
SI Derived Quantity 

s^{1}
SI Base Expression 

This unit is defined as the activity of a quantity of radioactive material in which one nucleus decays per second and is equivalent to an inverse second, s^{−1}.Named after

Becquerel 
Becquerel, Bq
SI Derived Unit 

Activity re Radionuclide
SI Derived Quantity 

s^{1}
SI Base Expression 

This unit is defined as the activity of a quantity of radioactive material in which one nucleus decays per second and is equivalent to an inverse second, s^{−1}.Named after

Becquerel 
Becquerel, Bq
SI Derived Unit 

Activity re Radionuclide
SI Derived Quantity 

s^{1}
SI Base Expression 

This unit is defined as the activity of a quantity of radioactive material in which one nucleus decays per second and is equivalent to an inverse second, s^{−1}.Named after

Coulomb 
Coulomb, C
SI Derived Unit 

Electric Charge, Amount of Electricity
SI Derived Quantity 

A·s
SI Base Expression 

This base unit of electrical charge is equal to 6.25 X 10^{18} electrons. Named for Charles Coulomb, the French physicist who pioneered research into magnetism and electricity, whom also formulated Coulomb’s law which states that the force of attraction or repulsion between two charged bodies is equal to the product of the two charges and is inversely proportional to the square of the distance between them.Named after Charles Augustin de Coulomb 
Coulomb 
Coulomb, C
SI Derived Unit 

Electric Charge, Amount of Electricity
SI Derived Quantity 

A·s
SI Base Expression 

This base unit of electrical charge is equal to 6.25 X 10^{18} electrons. Named for Charles Coulomb, the French physicist who pioneered research into magnetism and electricity, whom also formulated Coulomb’s law which states that the force of attraction or repulsion between two charged bodies is equal to the product of the two charges and is inversely proportional to the square of the distance between them.Named after

Coulomb 
Coulomb, C
SI Derived Unit 

Electric Charge, Amount of Electricity
SI Derived Quantity 

A·s
SI Base Expression 

This base unit of electrical charge is equal to 6.25 X 10^{18} electrons. Named for Charles Coulomb, the French physicist who pioneered research into magnetism and electricity, whom also formulated Coulomb’s law which states that the force of attraction or repulsion between two charged bodies is equal to the product of the two charges and is inversely proportional to the square of the distance between them.Named after

Coulomb 
Coulomb, C
SI Derived Unit 

Electric Charge, Amount of Electricity
SI Derived Quantity 

A·s
SI Base Expression 

This base unit of electrical charge is equal to 6.25 X 10^{18} electrons. Named for Charles Coulomb, the French physicist who pioneered research into magnetism and electricity, whom also formulated Coulomb’s law which states that the force of attraction or repulsion between two charged bodies is equal to the product of the two charges and is inversely proportional to the square of the distance between them.Named after

Coulomb 
Coulomb, C
SI Derived Unit 

Electric Charge, Amount of Electricity
SI Derived Quantity 

A·s
SI Base Expression 

This base unit of electrical charge is equal to 6.25 X 10^{18} electrons. Named for Charles Coulomb, the French physicist who pioneered research into magnetism and electricity, whom also formulated Coulomb’s law which states that the force of attraction or repulsion between two charged bodies is equal to the product of the two charges and is inversely proportional to the square of the distance between them.Named after

Degrees Celsius 
Degrees Celsius, °C
SI Derived Unit 

Celsius Temperature
SI Derived Quantity 

K
SI Base Expression 

Celsius, historically known as centigrade, is a scale and unit of measurement for temperature. From 1744 to 1954, 0 °C was defined as the freezing point of water and 100 °C was defined as the boiling point of water, both at a pressure of one standard atmosphere with mercury being the working material. Absolute zero, the lowest temperature possible, is defined as being precisely 0 K and −273.15 °C.Named after Anders Celsius 
Degrees Celsius 
Degrees Celsius, °C
SI Derived Unit 

Celsius Temperature
SI Derived Quantity 

K
SI Base Expression 

Celsius, historically known as centigrade, is a scale and unit of measurement for temperature. From 1744 to 1954, 0 °C was defined as the freezing point of water and 100 °C was defined as the boiling point of water, both at a pressure of one standard atmosphere with mercury being the working material. Absolute zero, the lowest temperature possible, is defined as being precisely 0 K and −273.15 °C.Named after

Degrees Celsius 
Degrees Celsius, °C
SI Derived Unit 

Celsius Temperature
SI Derived Quantity 

K
SI Base Expression 

Celsius, historically known as centigrade, is a scale and unit of measurement for temperature. From 1744 to 1954, 0 °C was defined as the freezing point of water and 100 °C was defined as the boiling point of water, both at a pressure of one standard atmosphere with mercury being the working material. Absolute zero, the lowest temperature possible, is defined as being precisely 0 K and −273.15 °C.Named after

Degrees Celsius 
Degrees Celsius, °C
SI Derived Unit 

Celsius Temperature
SI Derived Quantity 

K
SI Base Expression 

Celsius, historically known as centigrade, is a scale and unit of measurement for temperature. From 1744 to 1954, 0 °C was defined as the freezing point of water and 100 °C was defined as the boiling point of water, both at a pressure of one standard atmosphere with mercury being the working material. Absolute zero, the lowest temperature possible, is defined as being precisely 0 K and −273.15 °C.Named after

Degrees Celsius 
Degrees Celsius, °C
SI Derived Unit 

Celsius Temperature
SI Derived Quantity 

K
SI Base Expression 

Celsius, historically known as centigrade, is a scale and unit of measurement for temperature. From 1744 to 1954, 0 °C was defined as the freezing point of water and 100 °C was defined as the boiling point of water, both at a pressure of one standard atmosphere with mercury being the working material. Absolute zero, the lowest temperature possible, is defined as being precisely 0 K and −273.15 °C.Named after

Farad 
Farad, F
SI Derived Unit 

Capacitance
SI Derived Quantity 

kg^{−1}·m^{−2}·s^{4}·A^{2}
SI Base Expression 

One farad of capacitance will store one coulomb of charge when the charging force is one volt. Since the farad is a very large unit, capacitance will more commonly expressed as microfarad (uF) or picofarad (pF) values.Named after Michael Faraday 
Farad 
Farad, F
SI Derived Unit 

Capacitance
SI Derived Quantity 

kg^{−1}·m^{−2}·s^{4}·A^{2}
SI Base Expression 

One farad of capacitance will store one coulomb of charge when the charging force is one volt. Since the farad is a very large unit, capacitance will more commonly expressed as microfarad (uF) or picofarad (pF) values.Named after

Farad 
Farad, F
SI Derived Unit 

Capacitance
SI Derived Quantity 

kg^{−1}·m^{−2}·s^{4}·A^{2}
SI Base Expression 

One farad of capacitance will store one coulomb of charge when the charging force is one volt. Since the farad is a very large unit, capacitance will more commonly expressed as microfarad (uF) or picofarad (pF) values.Named after

Farad 
Farad, F
SI Derived Unit 

Capacitance
SI Derived Quantity 

kg^{−1}·m^{−2}·s^{4}·A^{2}
SI Base Expression 

One farad of capacitance will store one coulomb of charge when the charging force is one volt. Since the farad is a very large unit, capacitance will more commonly expressed as microfarad (uF) or picofarad (pF) values.Named after

Farad 
Farad, F
SI Derived Unit 

Capacitance
SI Derived Quantity 

kg^{−1}·m^{−2}·s^{4}·A^{2}
SI Base Expression 

One farad of capacitance will store one coulomb of charge when the charging force is one volt. Since the farad is a very large unit, capacitance will more commonly expressed as microfarad (uF) or picofarad (pF) values.Named after

Gray 
Gray, Gy
SI Derived Unit 

Absorbed Dose, Specific Energy (Imparted), Kerma
SI Derived Quantity 

m^{2}·s^{−2}
SI Base Expression 

This unit is defined as the absorption of one joule of radiation energy per one kilogram of matter. It is used as a measure of absorbed dose, specific energy (imparted), and kerma (an acronym for “kinetic energy released per unit mass”). It is a physical quantity, and does not take into account any biological context. Unlike the pre1971 nonSI roentgen unit of radiation exposure, the Gray when used for absorbed dose is defined independently of any target material. When measuring kerma the reference target material must be defined explicitly, usually as dry air at standard temperature and pressure.Named after Louis Harold Gray 
Gray 
Gray, Gy
SI Derived Unit 

Absorbed Dose, Specific Energy (Imparted), Kerma
SI Derived Quantity 

m^{2}·s^{−2}
SI Base Expression 

This unit is defined as the absorption of one joule of radiation energy per one kilogram of matter. It is used as a measure of absorbed dose, specific energy (imparted), and kerma (an acronym for “kinetic energy released per unit mass”). It is a physical quantity, and does not take into account any biological context. Unlike the pre1971 nonSI roentgen unit of radiation exposure, the Gray when used for absorbed dose is defined independently of any target material. When measuring kerma the reference target material must be defined explicitly, usually as dry air at standard temperature and pressure.Named after

Gray 
Gray, Gy
SI Derived Unit 

Absorbed Dose, Specific Energy (Imparted), Kerma
SI Derived Quantity 

m^{2}·s^{−2}
SI Base Expression 

This unit is defined as the absorption of one joule of radiation energy per one kilogram of matter. It is used as a measure of absorbed dose, specific energy (imparted), and kerma (an acronym for “kinetic energy released per unit mass”). It is a physical quantity, and does not take into account any biological context. Unlike the pre1971 nonSI roentgen unit of radiation exposure, the Gray when used for absorbed dose is defined independently of any target material. When measuring kerma the reference target material must be defined explicitly, usually as dry air at standard temperature and pressure.Named after

Gray 
Gray, Gy
SI Derived Unit 

Absorbed Dose, Specific Energy (Imparted), Kerma
SI Derived Quantity 

m^{2}·s^{−2}
SI Base Expression 

This unit is defined as the absorption of one joule of radiation energy per one kilogram of matter. It is used as a measure of absorbed dose, specific energy (imparted), and kerma (an acronym for “kinetic energy released per unit mass”). It is a physical quantity, and does not take into account any biological context. Unlike the pre1971 nonSI roentgen unit of radiation exposure, the Gray when used for absorbed dose is defined independently of any target material. When measuring kerma the reference target material must be defined explicitly, usually as dry air at standard temperature and pressure.Named after

Gray 
Gray, Gy
SI Derived Unit 

Absorbed Dose, Specific Energy (Imparted), Kerma
SI Derived Quantity 

m^{2}·s^{−2}
SI Base Expression 

This unit is defined as the absorption of one joule of radiation energy per one kilogram of matter. It is used as a measure of absorbed dose, specific energy (imparted), and kerma (an acronym for “kinetic energy released per unit mass”). It is a physical quantity, and does not take into account any biological context. Unlike the pre1971 nonSI roentgen unit of radiation exposure, the Gray when used for absorbed dose is defined independently of any target material. When measuring kerma the reference target material must be defined explicitly, usually as dry air at standard temperature and pressure.Named after

Henry 
Henry, H
SI Derived Unit 

Inductance
SI Derived Quantity 

kg · m^{2} · s^{−2} · A^{−2}
SI Base Expression 

This is the unit of inductance in which an induced electromotive force of one volt is produced when the current is varied at the rate of one ampere per second.Named after Joseph Henry 
Henry 
Henry, H
SI Derived Unit 

Inductance
SI Derived Quantity 

kg · m^{2} · s^{−2} · A^{−2}
SI Base Expression 

This is the unit of inductance in which an induced electromotive force of one volt is produced when the current is varied at the rate of one ampere per second.Named after

Henry 
Henry, H
SI Derived Unit 

Inductance
SI Derived Quantity 

kg · m^{2} · s^{−2} · A^{−2}
SI Base Expression 

This is the unit of inductance in which an induced electromotive force of one volt is produced when the current is varied at the rate of one ampere per second.Named after

Henry 
Henry, H
SI Derived Unit 

Inductance
SI Derived Quantity 

kg · m^{2} · s^{−2} · A^{−2}
SI Base Expression 

This is the unit of inductance in which an induced electromotive force of one volt is produced when the current is varied at the rate of one ampere per second.Named after

Henry 
Henry, H
SI Derived Unit 

Inductance
SI Derived Quantity 

kg · m^{2} · s^{−2} · A^{−2}
SI Base Expression 

This is the unit of inductance in which an induced electromotive force of one volt is produced when the current is varied at the rate of one ampere per second.Named after

Hertz 
Hertz, Hz
SI Derived Unit 

Frequency
SI Derived Quantity 

s^{1}
SI Base Expression 

This unit of frequency is equal to cycles per second. In defining the second, “the standard to be employed is the transition between the hyperfine levels F = 4, M = 0 and F = 3, M = 0 of the ground state 2S_{1/2} of the caesium 133 atom, unperturbed by external fields, and that the frequency of this transition is assigned the value 9,192,631,770 hertz”, effectively defining the hertz and the second simultaneously.Named after Heinrich Hertz 
Hertz 
Hertz, Hz
SI Derived Unit 

Frequency
SI Derived Quantity 

s^{1}
SI Base Expression 

This unit of frequency is equal to cycles per second. In defining the second, “the standard to be employed is the transition between the hyperfine levels F = 4, M = 0 and F = 3, M = 0 of the ground state 2S_{1/2} of the caesium 133 atom, unperturbed by external fields, and that the frequency of this transition is assigned the value 9,192,631,770 hertz”, effectively defining the hertz and the second simultaneously.Named after

Hertz 
Hertz, Hz
SI Derived Unit 

Frequency
SI Derived Quantity 

s^{1}
SI Base Expression 

This unit of frequency is equal to cycles per second. In defining the second, “the standard to be employed is the transition between the hyperfine levels F = 4, M = 0 and F = 3, M = 0 of the ground state 2S_{1/2} of the caesium 133 atom, unperturbed by external fields, and that the frequency of this transition is assigned the value 9,192,631,770 hertz”, effectively defining the hertz and the second simultaneously.Named after

Hertz 
Hertz, Hz
SI Derived Unit 

Frequency
SI Derived Quantity 

s^{1}
SI Base Expression 

This unit of frequency is equal to cycles per second. In defining the second, “the standard to be employed is the transition between the hyperfine levels F = 4, M = 0 and F = 3, M = 0 of the ground state 2S_{1/2} of the caesium 133 atom, unperturbed by external fields, and that the frequency of this transition is assigned the value 9,192,631,770 hertz”, effectively defining the hertz and the second simultaneously.Named after

Hertz 
Hertz, Hz
SI Derived Unit 

Frequency
SI Derived Quantity 

s^{1}
SI Base Expression 

This unit of frequency is equal to cycles per second. In defining the second, “the standard to be employed is the transition between the hyperfine levels F = 4, M = 0 and F = 3, M = 0 of the ground state 2S_{1/2} of the caesium 133 atom, unperturbed by external fields, and that the frequency of this transition is assigned the value 9,192,631,770 hertz”, effectively defining the hertz and the second simultaneously.Named after

Joule 
Joule, J
SI Derived Unit 

Energy, Work, Amount of Heat
SI Derived Quantity 

kg·m^{2}·s^{−2}
SI Base Expression 

This is the basic unit of electrical, mechanical, and thermal energy. As a unit of electrical energy it is equal to the energy carried by 1 coulomb of charge being propelled by an electromotive force of 1 volt.Named after Joseph Henry 
Joule 
Joule, J
SI Derived Unit 

Energy, Work, Amount of Heat
SI Derived Quantity 

kg·m^{2}·s^{−2}
SI Base Expression 

This is the basic unit of electrical, mechanical, and thermal energy. As a unit of electrical energy it is equal to the energy carried by 1 coulomb of charge being propelled by an electromotive force of 1 volt.Named after

Joule 
Joule, J
SI Derived Unit 

Energy, Work, Amount of Heat
SI Derived Quantity 

kg·m^{2}·s^{−2}
SI Base Expression 

This is the basic unit of electrical, mechanical, and thermal energy. As a unit of electrical energy it is equal to the energy carried by 1 coulomb of charge being propelled by an electromotive force of 1 volt.Named after

Joule 
Joule, J
SI Derived Unit 

Energy, Work, Amount of Heat
SI Derived Quantity 

kg·m^{2}·s^{−2}
SI Base Expression 

This is the basic unit of electrical, mechanical, and thermal energy. As a unit of electrical energy it is equal to the energy carried by 1 coulomb of charge being propelled by an electromotive force of 1 volt.Named after

Joule 
Joule, J
SI Derived Unit 

Energy, Work, Amount of Heat
SI Derived Quantity 

kg·m^{2}·s^{−2}
SI Base Expression 

This is the basic unit of electrical, mechanical, and thermal energy. As a unit of electrical energy it is equal to the energy carried by 1 coulomb of charge being propelled by an electromotive force of 1 volt.Named after

Katal 
Katal, kat
SI Derived Unit 

Catalytic Activity
SI Derived Quantity 

mol · s^{1}
SI Base Expression 

This is a unit for quantifying the catalytic activity of enzymes (measuring the enzymatic activity level in enzyme catalysis) and other catalysts. The katal is not used to express the rate of a reaction; that is expressed in units of concentration per second (or moles per litre per second). It is used to express catalytic activity which is a property of the catalyst. 
Katal 
Katal, kat
SI Derived Unit 

Catalytic Activity
SI Derived Quantity 

mol · s^{1}
SI Base Expression 

This is a unit for quantifying the catalytic activity of enzymes (measuring the enzymatic activity level in enzyme catalysis) and other catalysts. The katal is not used to express the rate of a reaction; that is expressed in units of concentration per second (or moles per litre per second). It is used to express catalytic activity which is a property of the catalyst. 
Katal 
Katal, kat
SI Derived Unit 

Catalytic Activity
SI Derived Quantity 

mol · s^{1}
SI Base Expression 

This is a unit for quantifying the catalytic activity of enzymes (measuring the enzymatic activity level in enzyme catalysis) and other catalysts. The katal is not used to express the rate of a reaction; that is expressed in units of concentration per second (or moles per litre per second). It is used to express catalytic activity which is a property of the catalyst. 
Katal 
Katal, kat
SI Derived Unit 

Catalytic Activity
SI Derived Quantity 

mol · s^{1}
SI Base Expression 

This is a unit for quantifying the catalytic activity of enzymes (measuring the enzymatic activity level in enzyme catalysis) and other catalysts. The katal is not used to express the rate of a reaction; that is expressed in units of concentration per second (or moles per litre per second). It is used to express catalytic activity which is a property of the catalyst. 
Katal 
Katal, kat
SI Derived Unit 

Catalytic Activity
SI Derived Quantity 

mol · s^{1}
SI Base Expression 

This is a unit for quantifying the catalytic activity of enzymes (measuring the enzymatic activity level in enzyme catalysis) and other catalysts. The katal is not used to express the rate of a reaction; that is expressed in units of concentration per second (or moles per litre per second). It is used to express catalytic activity which is a property of the catalyst. 
Lumen 
Lumen, lm
SI Derived Unit 

Luminous Flux
SI Derived Quantity 

cd · sr
SI Base Expression 

This is a measure of the total “amount” of visible light emitted by a source. Luminous flux differs from power (Radiant Flux) in that luminous flux measurements reflect the varying sensitivity of the human eye to different wavelengths of light. Radiant flux measurements indicate the total power of all electromagnetic waves emitted, independent of the eye’s ability to perceive it. Lumens are related to lux in that one lux is one lumen per square meter. 
Lumen 
Lumen, lm
SI Derived Unit 

Luminous Flux
SI Derived Quantity 

cd · sr
SI Base Expression 

This is a measure of the total “amount” of visible light emitted by a source. Luminous flux differs from power (Radiant Flux) in that luminous flux measurements reflect the varying sensitivity of the human eye to different wavelengths of light. Radiant flux measurements indicate the total power of all electromagnetic waves emitted, independent of the eye’s ability to perceive it. Lumens are related to lux in that one lux is one lumen per square meter. 
Lumen 
Lumen, lm
SI Derived Unit 

Luminous Flux
SI Derived Quantity 

cd · sr
SI Base Expression 

This is a measure of the total “amount” of visible light emitted by a source. Luminous flux differs from power (Radiant Flux) in that luminous flux measurements reflect the varying sensitivity of the human eye to different wavelengths of light. Radiant flux measurements indicate the total power of all electromagnetic waves emitted, independent of the eye’s ability to perceive it. Lumens are related to lux in that one lux is one lumen per square meter. 
Lumen 
Lumen, lm
SI Derived Unit 

Luminous Flux
SI Derived Quantity 

cd · sr
SI Base Expression 

This is a measure of the total “amount” of visible light emitted by a source. Luminous flux differs from power (Radiant Flux) in that luminous flux measurements reflect the varying sensitivity of the human eye to different wavelengths of light. Radiant flux measurements indicate the total power of all electromagnetic waves emitted, independent of the eye’s ability to perceive it. Lumens are related to lux in that one lux is one lumen per square meter. 
Lumen 
Lumen, lm
SI Derived Unit 

Luminous Flux
SI Derived Quantity 

cd · sr
SI Base Expression 

This is a measure of the total “amount” of visible light emitted by a source. Luminous flux differs from power (Radiant Flux) in that luminous flux measurements reflect the varying sensitivity of the human eye to different wavelengths of light. Radiant flux measurements indicate the total power of all electromagnetic waves emitted, independent of the eye’s ability to perceive it. Lumens are related to lux in that one lux is one lumen per square meter. 
Lux 
Lux, lx
SI Derived Unit 

Illuminance
SI Derived Quantity 

cd · sr · m^{−2}
SI Base Expression 

This is a measure of how much luminous flux (lumens) is spread over a given area. One lux is equal to one lumen per square metre. 
Lux 
Lux, lx
SI Derived Unit 

Illuminance
SI Derived Quantity 

cd · sr · m^{−2}
SI Base Expression 

This is a measure of how much luminous flux (lumens) is spread over a given area. One lux is equal to one lumen per square metre. 
Lux 
Lux, lx
SI Derived Unit 

Illuminance
SI Derived Quantity 

cd · sr · m^{−2}
SI Base Expression 

This is a measure of how much luminous flux (lumens) is spread over a given area. One lux is equal to one lumen per square metre. 
Lux 
Lux, lx
SI Derived Unit 

Illuminance
SI Derived Quantity 

cd · sr · m^{−2}
SI Base Expression 

This is a measure of how much luminous flux (lumens) is spread over a given area. One lux is equal to one lumen per square metre. 
Lux 
Lux, lx
SI Derived Unit 

Illuminance
SI Derived Quantity 

cd · sr · m^{−2}
SI Base Expression 

This is a measure of how much luminous flux (lumens) is spread over a given area. One lux is equal to one lumen per square metre. 
Newton 
Newton, N
SI Derived Unit 

Force
SI Derived Quantity 

kg · m · s^{−2}
SI Base Expression 

Force (F) is any interaction when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity, which includes to begin moving from a state of rest, as in to accelerate. Weight (W) of an object is the force on the object due to gravity. Weight is the product of the mass (m) of the object and the magnitude of the local gravitational acceleration (g), thus: W = mg.Named after Sir Isaac Newton 
Newton 
Newton, N
SI Derived Unit 

Force
SI Derived Quantity 

kg · m · s^{−2}
SI Base Expression 

Force (F) is any interaction when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity, which includes to begin moving from a state of rest, as in to accelerate. Weight (W) of an object is the force on the object due to gravity. Weight is the product of the mass (m) of the object and the magnitude of the local gravitational acceleration (g), thus: W = mg.Named after

Newton 
Newton, N
SI Derived Unit 

Force
SI Derived Quantity 

kg · m · s^{−2}
SI Base Expression 

Force (F) is any interaction when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity, which includes to begin moving from a state of rest, as in to accelerate. Weight (W) of an object is the force on the object due to gravity. Weight is the product of the mass (m) of the object and the magnitude of the local gravitational acceleration (g), thus: W = mg.Named after

Newton 
Newton, N
SI Derived Unit 

Force
SI Derived Quantity 

kg · m · s^{−2}
SI Base Expression 

Force (F) is any interaction when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity, which includes to begin moving from a state of rest, as in to accelerate. Weight (W) of an object is the force on the object due to gravity. Weight is the product of the mass (m) of the object and the magnitude of the local gravitational acceleration (g), thus: W = mg.Named after

Newton 
Newton, N
SI Derived Unit 

Force
SI Derived Quantity 

kg · m · s^{−2}
SI Base Expression 

Force (F) is any interaction when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity, which includes to begin moving from a state of rest, as in to accelerate. Weight (W) of an object is the force on the object due to gravity. Weight is the product of the mass (m) of the object and the magnitude of the local gravitational acceleration (g), thus: W = mg.Named after

Ohm 
Ohm, Ω
SI Derived Unit 

Electric Resistance
SI Derived Quantity 

kg · m^{2} · s^{−3} · A^{−2}
SI Base Expression 

The ohm is defined as an electrical resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere, the conductor not being the seat of any electromotive force. In alternating current circuits, electrical impedance is also measured in ohms (Ω).Named after Georg Simon Ohm 
Ohm 
Ohm, Ω
SI Derived Unit 

Electric Resistance
SI Derived Quantity 

kg · m^{2} · s^{−3} · A^{−2}
SI Base Expression 

The ohm is defined as an electrical resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere, the conductor not being the seat of any electromotive force. In alternating current circuits, electrical impedance is also measured in ohms (Ω).Named after

Ohm 
Ohm, Ω
SI Derived Unit 

Electric Resistance
SI Derived Quantity 

kg · m^{2} · s^{−3} · A^{−2}
SI Base Expression 

The ohm is defined as an electrical resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere, the conductor not being the seat of any electromotive force. In alternating current circuits, electrical impedance is also measured in ohms (Ω).Named after

Ohm 
Ohm, Ω
SI Derived Unit 

Electric Resistance
SI Derived Quantity 

kg · m^{2} · s^{−3} · A^{−2}
SI Base Expression 

The ohm is defined as an electrical resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere, the conductor not being the seat of any electromotive force. In alternating current circuits, electrical impedance is also measured in ohms (Ω).Named after

Ohm 
Ohm, Ω
SI Derived Unit 

Electric Resistance
SI Derived Quantity 

kg · m^{2} · s^{−3} · A^{−2}
SI Base Expression 

The ohm is defined as an electrical resistance between two points of a conductor when a constant potential difference of 1 volt, applied to these points, produces in the conductor a current of 1 ampere, the conductor not being the seat of any electromotive force. In alternating current circuits, electrical impedance is also measured in ohms (Ω).Named after

Pascal 
Pascal, Pa
SI Derived Unit 

Pressure, Stress
SI Derived Quantity 

kg · m^{1} · s^{−2}
SI Base Expression 

The pascal (Pa), is one newton per square metre. Pressure (P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure. Multiple units of the pascal are the hectopascal (1 hPa ≡ 100 Pa) which is equal to 1 mbar, the kilopascal (1 kPa ≡ 1,000 Pa), the megapascal (1 MPa ≡ 1,000,000 Pa), and the gigapascal (1 GPa ≡ 1,000,000,000 Pa). The unit of measurement called the standard atmosphere (atm) is defined as 101.325 kPa and approximates to the average pressure at sealevel at 45° N.Named after Blaise Pascal 
Pascal 
Pascal, Pa
SI Derived Unit 

Pressure, Stress
SI Derived Quantity 

kg · m^{1} · s^{−2}
SI Base Expression 

The pascal (Pa), is one newton per square metre. Pressure (P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure. Multiple units of the pascal are the hectopascal (1 hPa ≡ 100 Pa) which is equal to 1 mbar, the kilopascal (1 kPa ≡ 1,000 Pa), the megapascal (1 MPa ≡ 1,000,000 Pa), and the gigapascal (1 GPa ≡ 1,000,000,000 Pa). The unit of measurement called the standard atmosphere (atm) is defined as 101.325 kPa and approximates to the average pressure at sealevel at 45° N.Named after

Pascal 
Pascal, Pa
SI Derived Unit 

Pressure, Stress
SI Derived Quantity 

kg · m^{1} · s^{−2}
SI Base Expression 

The pascal (Pa), is one newton per square metre. Pressure (P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure. Multiple units of the pascal are the hectopascal (1 hPa ≡ 100 Pa) which is equal to 1 mbar, the kilopascal (1 kPa ≡ 1,000 Pa), the megapascal (1 MPa ≡ 1,000,000 Pa), and the gigapascal (1 GPa ≡ 1,000,000,000 Pa). The unit of measurement called the standard atmosphere (atm) is defined as 101.325 kPa and approximates to the average pressure at sealevel at 45° N.Named after

Pascal 
Pascal, Pa
SI Derived Unit 

Pressure, Stress
SI Derived Quantity 

kg · m^{1} · s^{−2}
SI Base Expression 

The pascal (Pa), is one newton per square metre. Pressure (P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure. Multiple units of the pascal are the hectopascal (1 hPa ≡ 100 Pa) which is equal to 1 mbar, the kilopascal (1 kPa ≡ 1,000 Pa), the megapascal (1 MPa ≡ 1,000,000 Pa), and the gigapascal (1 GPa ≡ 1,000,000,000 Pa). The unit of measurement called the standard atmosphere (atm) is defined as 101.325 kPa and approximates to the average pressure at sealevel at 45° N.Named after

Pascal 
Pascal, Pa
SI Derived Unit 

Pressure, Stress
SI Derived Quantity 

kg · m^{1} · s^{−2}
SI Base Expression 

The pascal (Pa), is one newton per square metre. Pressure (P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure. Multiple units of the pascal are the hectopascal (1 hPa ≡ 100 Pa) which is equal to 1 mbar, the kilopascal (1 kPa ≡ 1,000 Pa), the megapascal (1 MPa ≡ 1,000,000 Pa), and the gigapascal (1 GPa ≡ 1,000,000,000 Pa). The unit of measurement called the standard atmosphere (atm) is defined as 101.325 kPa and approximates to the average pressure at sealevel at 45° N.Named after

Radian 
Radian, rad
SI Derived Unit 

Plane Angle
SI Derived Quantity 

m/m
SI Base Expression 

An angle’s measurement in radians is numerically equal to the length of a corresponding arc of a unit circle; one radian is just under 57.3 degrees (when the arc length is equal to the radius). One radian is equal to 180/π degrees. To convert from radians to degrees, multiply by 180/π.Named after Roger Cotes 
Radian 
Radian, rad
SI Derived Unit 

Plane Angle
SI Derived Quantity 

m/m
SI Base Expression 

An angle’s measurement in radians is numerically equal to the length of a corresponding arc of a unit circle; one radian is just under 57.3 degrees (when the arc length is equal to the radius). One radian is equal to 180/π degrees. To convert from radians to degrees, multiply by 180/π.Named after

Radian 
Radian, rad
SI Derived Unit 

Plane Angle
SI Derived Quantity 

m/m
SI Base Expression 

An angle’s measurement in radians is numerically equal to the length of a corresponding arc of a unit circle; one radian is just under 57.3 degrees (when the arc length is equal to the radius). One radian is equal to 180/π degrees. To convert from radians to degrees, multiply by 180/π.Named after

Radian 
Radian, rad
SI Derived Unit 

Plane Angle
SI Derived Quantity 

m/m
SI Base Expression 

An angle’s measurement in radians is numerically equal to the length of a corresponding arc of a unit circle; one radian is just under 57.3 degrees (when the arc length is equal to the radius). One radian is equal to 180/π degrees. To convert from radians to degrees, multiply by 180/π.Named after

Radian 
Radian, rad
SI Derived Unit 

Plane Angle
SI Derived Quantity 

m/m
SI Base Expression 

An angle’s measurement in radians is numerically equal to the length of a corresponding arc of a unit circle; one radian is just under 57.3 degrees (when the arc length is equal to the radius). One radian is equal to 180/π degrees. To convert from radians to degrees, multiply by 180/π.Named after

Siemen 
Siemen, S
SI Derived Unit 

Electric Conductance
SI Derived Quantity 

kg^{−1} · m^{−2} · s^{3} · A^{2}
SI Base Expression 

This is the unit of electric conductance, electric susceptance and electric admittance which are the reciprocals of resistance, reactance, and impedance. One siemens is equal to the reciprocal of one ohm, and is also referred to as the mho.Named after Ernst Werner von Siemens 
Siemen 
Siemen, S
SI Derived Unit 

Electric Conductance
SI Derived Quantity 

kg^{−1} · m^{−2} · s^{3} · A^{2}
SI Base Expression 

This is the unit of electric conductance, electric susceptance and electric admittance which are the reciprocals of resistance, reactance, and impedance. One siemens is equal to the reciprocal of one ohm, and is also referred to as the mho.Named after

Siemen 
Siemen, S
SI Derived Unit 

Electric Conductance
SI Derived Quantity 

kg^{−1} · m^{−2} · s^{3} · A^{2}
SI Base Expression 

This is the unit of electric conductance, electric susceptance and electric admittance which are the reciprocals of resistance, reactance, and impedance. One siemens is equal to the reciprocal of one ohm, and is also referred to as the mho.Named after

Siemen 
Siemen, S
SI Derived Unit 

Electric Conductance
SI Derived Quantity 

kg^{−1} · m^{−2} · s^{3} · A^{2}
SI Base Expression 

This is the unit of electric conductance, electric susceptance and electric admittance which are the reciprocals of resistance, reactance, and impedance. One siemens is equal to the reciprocal of one ohm, and is also referred to as the mho.Named after

Siemen 
Siemen, S
SI Derived Unit 

Electric Conductance
SI Derived Quantity 

kg^{−1} · m^{−2} · s^{3} · A^{2}
SI Base Expression 

This is the unit of electric conductance, electric susceptance and electric admittance which are the reciprocals of resistance, reactance, and impedance. One siemens is equal to the reciprocal of one ohm, and is also referred to as the mho.Named after

Sievert 
Sievert, Sv
SI Derived Unit 

Ambient, Directional, Dose and Personal Dose Equivalent
SI Derived Quantity 

m^{2} · s^{−2}
SI Base Expression 

This is a measure of the health effect of low levels of ionizing radiation on the human body. Quantities that are measured in sieverts are intended to represent the stochastic health risk, which for radiation dose assessment is defined as the probability of cancer induction and genetic. The sievert is used for radiation dose quantities such as equivalent dose, effective dose, and committed dose. It is used both to represent the risk of the effect of external radiation from sources outside the body, and the effect of internal irradiation due to inhaled or ingested radioactive substances. One sievert carries with it a 5.5% chance of eventually developing cancer.Named after Rolf Maximilian Sievert 
Sievert 
Sievert, Sv
SI Derived Unit 

Ambient, Directional, Dose and Personal Dose Equivalent
SI Derived Quantity 

m^{2} · s^{−2}
SI Base Expression 

This is a measure of the health effect of low levels of ionizing radiation on the human body. Quantities that are measured in sieverts are intended to represent the stochastic health risk, which for radiation dose assessment is defined as the probability of cancer induction and genetic. The sievert is used for radiation dose quantities such as equivalent dose, effective dose, and committed dose. It is used both to represent the risk of the effect of external radiation from sources outside the body, and the effect of internal irradiation due to inhaled or ingested radioactive substances. One sievert carries with it a 5.5% chance of eventually developing cancer.Named after

Sievert 
Sievert, Sv
SI Derived Unit 

Ambient, Directional, Dose and Personal Dose Equivalent
SI Derived Quantity 

m^{2} · s^{−2}
SI Base Expression 

This is a measure of the health effect of low levels of ionizing radiation on the human body. Quantities that are measured in sieverts are intended to represent the stochastic health risk, which for radiation dose assessment is defined as the probability of cancer induction and genetic. The sievert is used for radiation dose quantities such as equivalent dose, effective dose, and committed dose. It is used both to represent the risk of the effect of external radiation from sources outside the body, and the effect of internal irradiation due to inhaled or ingested radioactive substances. One sievert carries with it a 5.5% chance of eventually developing cancer.Named after

Sievert 
Sievert, Sv
SI Derived Unit 

Ambient, Directional, Dose and Personal Dose Equivalent
SI Derived Quantity 

m^{2} · s^{−2}
SI Base Expression 

This is a measure of the health effect of low levels of ionizing radiation on the human body. Quantities that are measured in sieverts are intended to represent the stochastic health risk, which for radiation dose assessment is defined as the probability of cancer induction and genetic. The sievert is used for radiation dose quantities such as equivalent dose, effective dose, and committed dose. It is used both to represent the risk of the effect of external radiation from sources outside the body, and the effect of internal irradiation due to inhaled or ingested radioactive substances. One sievert carries with it a 5.5% chance of eventually developing cancer.Named after

Sievert 
Sievert, Sv
SI Derived Unit 

Ambient, Directional, Dose and Personal Dose Equivalent
SI Derived Quantity 

m^{2} · s^{−2}
SI Base Expression 

This is a measure of the health effect of low levels of ionizing radiation on the human body. Quantities that are measured in sieverts are intended to represent the stochastic health risk, which for radiation dose assessment is defined as the probability of cancer induction and genetic. The sievert is used for radiation dose quantities such as equivalent dose, effective dose, and committed dose. It is used both to represent the risk of the effect of external radiation from sources outside the body, and the effect of internal irradiation due to inhaled or ingested radioactive substances. One sievert carries with it a 5.5% chance of eventually developing cancer.Named after

Steradian 
Steradian, sr
SI Derived Unit 

Solid Angle
SI Derived Quantity 

m^{2}/m^{2}
SI Base Expression 

Also known as the square radian, it is used in threedimensional geometry and is analogous to the radian which quantifies planar angles. This solid angle is the ratio between the area subtended and the square of its distance from the vertex: both the numerator and denominator of this ratio have dimension length squared. 
Steradian 
Steradian, sr
SI Derived Unit 

Solid Angle
SI Derived Quantity 

m^{2}/m^{2}
SI Base Expression 

Also known as the square radian, it is used in threedimensional geometry and is analogous to the radian which quantifies planar angles. This solid angle is the ratio between the area subtended and the square of its distance from the vertex: both the numerator and denominator of this ratio have dimension length squared. 
Steradian 
Steradian, sr
SI Derived Unit 

Solid Angle
SI Derived Quantity 

m^{2}/m^{2}
SI Base Expression 

Also known as the square radian, it is used in threedimensional geometry and is analogous to the radian which quantifies planar angles. This solid angle is the ratio between the area subtended and the square of its distance from the vertex: both the numerator and denominator of this ratio have dimension length squared. 
Steradian 
Steradian, sr
SI Derived Unit 

Solid Angle
SI Derived Quantity 

m^{2}/m^{2}
SI Base Expression 

Also known as the square radian, it is used in threedimensional geometry and is analogous to the radian which quantifies planar angles. This solid angle is the ratio between the area subtended and the square of its distance from the vertex: both the numerator and denominator of this ratio have dimension length squared. 
Steradian 
Steradian, sr
SI Derived Unit 

Solid Angle
SI Derived Quantity 

m^{2}/m^{2}
SI Base Expression 

Also known as the square radian, it is used in threedimensional geometry and is analogous to the radian which quantifies planar angles. This solid angle is the ratio between the area subtended and the square of its distance from the vertex: both the numerator and denominator of this ratio have dimension length squared. 
Tesla 
Tesla, T
SI Derived Unit 

Magnetic Flux Density
SI Derived Quantity 

kg · s^{−2} · A^{−1}
SI Base Expression 

This is the measurement for the strength of the magnetic field. One tesla is equal to one weber per square metre. A particle, that is carrying the charge of 1 coulomb, passing through a magnetic field of 1 tesla, perpendicular and at a speed of 1 metre per second, experiences a force of magnitude 1 newton.Named after Nicola Tesla 
Tesla 
Tesla, T
SI Derived Unit 

Magnetic Flux Density
SI Derived Quantity 

kg · s^{−2} · A^{−1}
SI Base Expression 

This is the measurement for the strength of the magnetic field. One tesla is equal to one weber per square metre. A particle, that is carrying the charge of 1 coulomb, passing through a magnetic field of 1 tesla, perpendicular and at a speed of 1 metre per second, experiences a force of magnitude 1 newton.Named after

Tesla 
Tesla, T
SI Derived Unit 

Magnetic Flux Density
SI Derived Quantity 

kg · s^{−2} · A^{−1}
SI Base Expression 

This is the measurement for the strength of the magnetic field. One tesla is equal to one weber per square metre. A particle, that is carrying the charge of 1 coulomb, passing through a magnetic field of 1 tesla, perpendicular and at a speed of 1 metre per second, experiences a force of magnitude 1 newton.Named after

Tesla 
Tesla, T
SI Derived Unit 

Magnetic Flux Density
SI Derived Quantity 

kg · s^{−2} · A^{−1}
SI Base Expression 

This is the measurement for the strength of the magnetic field. One tesla is equal to one weber per square metre. A particle, that is carrying the charge of 1 coulomb, passing through a magnetic field of 1 tesla, perpendicular and at a speed of 1 metre per second, experiences a force of magnitude 1 newton.Named after

Tesla 
Tesla, T
SI Derived Unit 

Magnetic Flux Density
SI Derived Quantity 

kg · s^{−2} · A^{−1}
SI Base Expression 

This is the measurement for the strength of the magnetic field. One tesla is equal to one weber per square metre. A particle, that is carrying the charge of 1 coulomb, passing through a magnetic field of 1 tesla, perpendicular and at a speed of 1 metre per second, experiences a force of magnitude 1 newton.Named after

Volt 
Volt, V
SI Derived Unit 

Electric Potential Difference, Electromotive Force
SI Derived Quantity 

kg · m^{2} · s^{−3} · A^{−1}
SI Base Expression 

This is the measurement for the strength of the magnetic field. One tesla is equal to one weber per square metre. A particle, that is carrying the charge of 1 coulomb, passing through a magnetic field of 1 tesla, perpendicular and at a speed of 1 metre per second, experiences a force of magnitude 1 newton.Named after Alessandro Giuseppe Antonio Anastasio Volta 
Volt 
Volt, V
SI Derived Unit 

Electric Potential Difference, Electromotive Force
SI Derived Quantity 

kg · m^{2} · s^{−3} · A^{−1}
SI Base Expression 

This is the measurement for the strength of the magnetic field. One tesla is equal to one weber per square metre. A particle, that is carrying the charge of 1 coulomb, passing through a magnetic field of 1 tesla, perpendicular and at a speed of 1 metre per second, experiences a force of magnitude 1 newton.Named after

Volt 
Volt, V
SI Derived Unit 

Electric Potential Difference, Electromotive Force
SI Derived Quantity 

kg · m^{2} · s^{−3} · A^{−1}
SI Base Expression 

This is the measurement for the strength of the magnetic field. One tesla is equal to one weber per square metre. A particle, that is carrying the charge of 1 coulomb, passing through a magnetic field of 1 tesla, perpendicular and at a speed of 1 metre per second, experiences a force of magnitude 1 newton.Named after

Volt 
Volt, V
SI Derived Unit 

Electric Potential Difference, Electromotive Force
SI Derived Quantity 

kg · m^{2} · s^{−3} · A^{−1}
SI Base Expression 

This is the measurement for the strength of the magnetic field. One tesla is equal to one weber per square metre. A particle, that is carrying the charge of 1 coulomb, passing through a magnetic field of 1 tesla, perpendicular and at a speed of 1 metre per second, experiences a force of magnitude 1 newton.Named after

Volt 
Volt, V
SI Derived Unit 

Electric Potential Difference, Electromotive Force
SI Derived Quantity 

kg · m^{2} · s^{−3} · A^{−1}
SI Base Expression 

This is the measurement for the strength of the magnetic field. One tesla is equal to one weber per square metre. A particle, that is carrying the charge of 1 coulomb, passing through a magnetic field of 1 tesla, perpendicular and at a speed of 1 metre per second, experiences a force of magnitude 1 newton.Named after

Watt 
Watt, W
SI Derived Unit 

Power, Radiant Flux
SI Derived Quantity 

kg · m^{2} · s^{−3}
SI Base Expression 

This unit is defined as joule per second and is used to express the rate of energy conversion or transfer with respect to time.Named after James Watt 
Watt 
Watt, W
SI Derived Unit 

Power, Radiant Flux
SI Derived Quantity 

kg · m^{2} · s^{−3}
SI Base Expression 

This unit is defined as joule per second and is used to express the rate of energy conversion or transfer with respect to time.Named after

Watt 
Watt, W
SI Derived Unit 

Power, Radiant Flux
SI Derived Quantity 

kg · m^{2} · s^{−3}
SI Base Expression 

This unit is defined as joule per second and is used to express the rate of energy conversion or transfer with respect to time.Named after

Watt 
Watt, W
SI Derived Unit 

Power, Radiant Flux
SI Derived Quantity 

kg · m^{2} · s^{−3}
SI Base Expression 

This unit is defined as joule per second and is used to express the rate of energy conversion or transfer with respect to time.Named after

Watt 
Watt, W
SI Derived Unit 

Power, Radiant Flux
SI Derived Quantity 

kg · m^{2} · s^{−3}
SI Base Expression 

This unit is defined as joule per second and is used to express the rate of energy conversion or transfer with respect to time.Named after

Webber 
Webber, Wb
SI Derived Unit 

Magnetic Flux
SI Derived Quantity 

kg · m^{2} · s^{−2} · A^{−1}
SI Base Expression 

This unit is defined as joule per second and is used to express the rate of energy conversion or transfer with respect to time. 
Webber 
Webber, Wb
SI Derived Unit 

Magnetic Flux
SI Derived Quantity 

kg · m^{2} · s^{−2} · A^{−1}
SI Base Expression 

This unit is defined as joule per second and is used to express the rate of energy conversion or transfer with respect to time. 
Webber 
Webber, Wb
SI Derived Unit 

Magnetic Flux
SI Derived Quantity 

kg · m^{2} · s^{−2} · A^{−1}
SI Base Expression 

This unit is defined as joule per second and is used to express the rate of energy conversion or transfer with respect to time. 
Webber 
Webber, Wb
SI Derived Unit 

Magnetic Flux
SI Derived Quantity 

kg · m^{2} · s^{−2} · A^{−1}
SI Base Expression 

This unit is defined as joule per second and is used to express the rate of energy conversion or transfer with respect to time. 
Webber 
Webber, Wb
SI Derived Unit 

Magnetic Flux
SI Derived Quantity 

kg · m^{2} · s^{−2} · A^{−1}
SI Base Expression 

This unit is defined as joule per second and is used to express the rate of energy conversion or transfer with respect to time. 
DECIMAL UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
DECIMAL UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
DECIMAL UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
DECIMAL UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
DECIMAL UNITS  
SI Prefixes (Decimal) 
N  S  K  P  D  
Yotta  Y  Septillion  10^{24}  1,000,000,000,000,000,000,000,000  
Zetta  Z  Sextillion  10^{21}  1,000,000,000,000,000,000,000  
Exa  E  Quintillion  10^{18}  1,000,000,000,000,000,000  
Peta  P  Quadrillion  10^{15}  1,000,000,000,000,000  
Tera  T  Trillion  10^{12}  1,000,000,000,000  
Giga  G  Billion  10^{9}  1,000,000,000  
Mega  M  Million  10^{6}  1,000,000  
Kilo  k  Thousand  10^{3}  1,000  
Hecto  h  Hundred  10^{2}  100  
Deca  da  Ten  10^{1}  10  
Unit  1  One  10^{0}  1  
Deci  d  Tenth  10^{1}  0.1  
Centi  c  Hundredth  10^{2}  0.01  
Milli  m  Thousandth  10^{3}  0.001  
Micro  μ  Millionth  10^{6}  0.000’001  
Nano  n  Billionth  10^{9}  0.000’000’001  
Pico  p  Trillionth  10^{12}  0.000’000’000’001  
Femto  f  Quadrillionth  10^{15}  0.000’000’000’000’001  
Atto  a  Quintillionth  10^{18}  0.000’000’000’000’000’001  
Zepto  z  Sextillionth  10^{21}  0.000’000’000’000’000’000’001  
Yocto  y  Septillionth  10^{24}  0.000’000’000’000’000’000’000’001 
SI Prefixes (Decimal) 
N  S  K  P  
Yotta  Y  Septillion  10^{24}  
Zetta  Z  Sextillion  10^{21}  
Exa  E  Quintillion  10^{18}  
Peta  P  Quadrillion  10^{15}  
Tera  T  Trillion  10^{12}  
Giga  G  Billion  10^{9}  
Mega  M  Million  10^{6}  
Kilo  k  Thousand  10^{3}  
Hecto  h  Hundred  10^{2}  
Deca  da  Ten  10^{1}  
Unit  1  One  10^{0}  
Deci  d  Tenth  10^{1}  
Centi  c  Hundredth  10^{2}  
Milli  m  Thousandth  10^{3}  
Micro  μ  Millionth  10^{6}  
Nano  n  Billionth  10^{9}  
Pico  p  Trillionth  10^{12}  
Femto  f  Quadrillionth  10^{15}  
Atto  a  Quintillionth  10^{18}  
Zepto  z  Sextillionth  10^{21}  
Yocto  y  Septillionth  10^{24} 
SI Prefixes (Decimal) 
N  S  K  P  
Yotta  Y  Septillion  10^{24}  
Zetta  Z  Sextillion  10^{21}  
Exa  E  Quintillion  10^{18}  
Peta  P  Quadrillion  10^{15}  
Tera  T  Trillion  10^{12}  
Giga  G  Billion  10^{9}  
Mega  M  Million  10^{6}  
Kilo  k  Thousand  10^{3}  
Hecto  h  Hundred  10^{2}  
Deca  da  Ten  10^{1}  
Unit  1  One  10^{0}  
Deci  d  Tenth  10^{1}  
Centi  c  Hundredth  10^{2}  
Milli  m  Thousandth  10^{3}  
Micro  μ  Millionth  10^{6}  
Nano  n  Billionth  10^{9}  
Pico  p  Trillionth  10^{12}  
Femto  f  Quadrillionth  10^{15}  
Atto  a  Quintillionth  10^{18}  
Zepto  z  Sextillionth  10^{21}  
Yocto  y  Septillionth  10^{24} 
SI Prefixes (Decimal) 
N  S  K  P  
Yotta  Y  Septillion  10^{24}  
Zetta  Z  Sextillion  10^{21}  
Exa  E  Quintillion  10^{18}  
Peta  P  Quadrillion  10^{15}  
Tera  T  Trillion  10^{12}  
Giga  G  Billion  10^{9}  
Mega  M  Million  10^{6}  
Kilo  k  Thousand  10^{3}  
Hecto  h  Hundred  10^{2}  
Deca  da  Ten  10^{1}  
Unit  1  One  10^{0}  
Deci  d  Tenth  10^{1}  
Centi  c  Hundredth  10^{2}  
Milli  m  Thousandth  10^{3}  
Micro  μ  Millionth  10^{6}  
Nano  n  Billionth  10^{9}  
Pico  p  Trillionth  10^{12}  
Femto  f  Quadrillionth  10^{15}  
Atto  a  Quintillionth  10^{18}  
Zepto  z  Sextillionth  10^{21}  
Yocto  y  Septillionth  10^{24} 
SI Prefixes (Decimal) 
N  S  K  P  
Yotta  Y  Septillion  10^{24}  
Zetta  Z  Sextillion  10^{21}  
Exa  E  Quintillion  10^{18}  
Peta  P  Quadrillion  10^{15}  
Tera  T  Trillion  10^{12}  
Giga  G  Billion  10^{9}  
Mega  M  Million  10^{6}  
Kilo  k  Thousand  10^{3}  
Hecto  h  Hundred  10^{2}  
Deca  da  Ten  10^{1}  
Unit  1  One  10^{0}  
Deci  d  Tenth  10^{1}  
Centi  c  Hundredth  10^{2}  
Milli  m  Thousandth  10^{3}  
Micro  μ  Millionth  10^{6}  
Nano  n  Billionth  10^{9}  
Pico  p  Trillionth  10^{12}  
Femto  f  Quadrillionth  10^{15}  
Atto  a  Quintillionth  10^{18}  
Zepto  z  Sextillionth  10^{21}  
Yocto  y  Septillionth  10^{24} 
BINARY UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
BINARY UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
BINARY UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
BINARY UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
BINARY UNITS  
SI Prefixes (Binary) 
N  S  K  P  D  
Yobi  Yi  Yottabinary  (2^{10})^{8}  1,208,925,819,614,629,174,706,176  
Zebi  Zi  Zettabinary  (2^{10})^{7}  1,180,591,620,717,411,303,424  
Exbi  Ei  Exabinary  (2^{10})^{6}  1,152,921,504,606,850,000  
Pebi  Pi  Petabinary  (2^{10})^{5}  1,125,899,906,842,620  
Tebi  Ti  Terabinary  (2^{10})^{4}  1,099,511,627,776  
Gibi  Gi  Gigabinary  (2^{10})^{3}  1,073,741,824  
Mebi  Mi  Megabinary  (2^{10})^{2}  1,048,576  
Kibi  Ki  Kilobinary  (2^{10})^{1}  1,024  
Unit  1  One  (10^{0})  1 
SI Prefixes (Binary) 
N  S  K  P  
Yobi  Yi  Yottabinary  (2^{10})^{8}  
Zebi  Zi  Zettabinary  (2^{10})^{7}  
Exbi  Ei  Exabinary  (2^{10})^{6}  
Pebi  Pi  Petabinary  (2^{10})^{5}  
Tebi  Ti  Terabinary  (2^{10})^{4}  
Gibi  Gi  Gigabinary  (2^{10})^{3}  
Mebi  Mi  Megabinary  (2^{10})^{2}  
Kibi  Ki  Kilobinary  (2^{10})^{1}  
Unit  1  One  (10^{0}) 
SI Prefixes (Binary) 
N  S  K  P  
Yobi  Yi  Yottabinary  (2^{10})^{8}  
Zebi  Zi  Zettabinary  (2^{10})^{7}  
Exbi  Ei  Exabinary  (2^{10})^{6}  
Pebi  Pi  Petabinary  (2^{10})^{5}  
Tebi  Ti  Terabinary  (2^{10})^{4}  
Gibi  Gi  Gigabinary  (2^{10})^{3}  
Mebi  Mi  Megabinary  (2^{10})^{2}  
Kibi  Ki  Kilobinary  (2^{10})^{1}  
Unit  1  One  (10^{0}) 
SI Prefixes (Binary) 
N  S  K  P  
Yobi  Yi  Yottabinary  (2^{10})^{8}  
Zebi  Zi  Zettabinary  (2^{10})^{7}  
Exbi  Ei  Exabinary  (2^{10})^{6}  
Pebi  Pi  Petabinary  (2^{10})^{5}  
Tebi  Ti  Terabinary  (2^{10})^{4}  
Gibi  Gi  Gigabinary  (2^{10})^{3}  
Mebi  Mi  Megabinary  (2^{10})^{2}  
Kibi  Ki  Kilobinary  (2^{10})^{1}  
Unit  1  One  (10^{0}) 
SI Prefixes (Binary) 
N  S  K  P  
Yobi  Yi  Yottabinary  (2^{10})^{8}  
Zebi  Zi  Zettabinary  (2^{10})^{7}  
Exbi  Ei  Exabinary  (2^{10})^{6}  
Pebi  Pi  Petabinary  (2^{10})^{5}  
Tebi  Ti  Terabinary  (2^{10})^{4}  
Gibi  Gi  Gigabinary  (2^{10})^{3}  
Mebi  Mi  Megabinary  (2^{10})^{2}  
Kibi  Ki  Kilobinary  (2^{10})^{1}  
Unit  1  One  (10^{0}) 
CONVERSION UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
CONVERSION UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
CONVERSION UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
CONVERSION UNITS  
BASE · DERIVED DECIMAL · BINARY · CONVERSION 
CONVERSION UNITS  
Conversion of SI to CGS Units 
SI Units (French: Système International d’Unités) Gaussian Units (CGS: CentimetreGramSecond) 

Electric Charge, q 1 C (SI) = (10^{−1} c) Fr (CGS) 

Electric Current, I 1 A (SI) = (10^{−1} c) Fr/s (CGS) 

Electric Potential, φ · V 1 V (SI) = (10^{8} csup>−1) statV (CGS) 

Electric Field, E 1 V/m (SI) = (10^{6} c^{−1}) statV/cm (CGS) 

Magnetic Induction, B 1 T (SI) = (10^{4}) Gs (CGS) 

Magnetic Field Strength, H 1 A/m (SI) = (4π 10^{−3}) Oe (CGS) 

Magnetic Dipole Moment, μ 1 A·m² (SI) = (10^{3}) erg/Gs (CGS) 

Magnetic Flux, Φ_{m} 1 Wb (SI) = (10^{8}) Gs·cm^{2} (CGS) 

Resistance, R 1 Ω (SI) = (10^{9} c^{−2}) s/cm (CGS) 

Resistivity, ρ 1 Ω·m (SI) = (10^{11} c^{−2}) s (CGS) 

Capacitance, C 1 F (SI) = (10^{−9} c^{2}) cm (CGS) 

Inductance, L 1 H (SI) = (10^{9} c^{−2}) s^{2}/cm (CGS) 

Conversion of SI to CGS Units 
Conversion of SI to CGS Units 
Electric Charge, q 1 C (SI) = (10^{−1} c) Fr (CGS) 

Electric Current, I 1 A (SI) = (10^{−1} c) Fr/s (CGS) 

Electric Potential, φ · V 1 V (SI) = (10^{8} csup>−1) statV (CGS) 

Electric Field, E 1 V/m (SI) = (10^{6} c^{−1}) statV/cm (CGS) 

Magnetic Induction, B 1 T (SI) = (10^{4}) Gs (CGS) 

Magnetic Field Strength, H 1 A/m (SI) = (4π 10^{−3}) Oe (CGS) 

Magnetic Dipole Moment, μ 1 A·m² (SI) = (10^{3}) erg/Gs (CGS) 

Magnetic Flux, Φ_{m} 1 Wb (SI) = (10^{8}) Gs·cm^{2} (CGS) 

Resistance, R 1 Ω (SI) = (10^{9} c^{−2}) s/cm (CGS) 

Resistivity, ρ 1 Ω·m (SI) = (10^{11} c^{−2}) s (CGS) 

Capacitance, C 1 F (SI) = (10^{−9} c^{2}) cm (CGS) 

Inductance, L 1 H (SI) = (10^{9} c^{−2}) s^{2}/cm (CGS) 

Conversion of SI to CGS Units 
Electric Charge, q 1 C (SI) = (10^{−1} c) Fr (CGS) 

Electric Current, I 1 A (SI) = (10^{−1} c) Fr/s (CGS) 

Electric Potential, φ · V 1 V (SI) = (10^{8} csup>−1) statV (CGS) 

Electric Field, E 1 V/m (SI) = (10^{6} c^{−1}) statV/cm (CGS) 

Magnetic Induction, B 1 T (SI) = (10^{4}) Gs (CGS) 

Magnetic Field Strength, H 1 A/m (SI) = (4π 10^{−3}) Oe (CGS) 

Magnetic Dipole Moment, μ 1 A·m² (SI) = (10^{3}) erg/Gs (CGS) 

Magnetic Flux, Φ_{m} 1 Wb (SI) = (10^{8}) Gs·cm^{2} (CGS) 

Resistance, R 1 Ω (SI) = (10^{9} c^{−2}) s/cm (CGS) 

Resistivity, ρ 1 Ω·m (SI) = (10^{11} c^{−2}) s (CGS) 

Capacitance, C 1 F (SI) = (10^{−9} c^{2}) cm (CGS) 

Inductance, L 1 H (SI) = (10^{9} c^{−2}) s^{2}/cm (CGS) 

Conversion of SI to CGS Units 
Electric Charge, q 1 C (SI) = (10^{−1} c) Fr (CGS) 

Electric Current, I 1 A (SI) = (10^{−1} c) Fr/s (CGS) 

Electric Potential, φ · V 1 V (SI) = (10^{8} csup>−1) statV (CGS) 

Electric Field, E 1 V/m (SI) = (10^{6} c^{−1}) statV/cm (CGS) 

Magnetic Induction, B 1 T (SI) = (10^{4}) Gs (CGS) 

Magnetic Field Strength, H 1 A/m (SI) = (4π 10^{−3}) Oe (CGS) 

Magnetic Dipole Moment, μ 1 A·m² (SI) = (10^{3}) erg/Gs (CGS) 

Magnetic Flux, Φ_{m} 1 Wb (SI) = (10^{8}) Gs·cm^{2} (CGS) 

Resistance, R 1 Ω (SI) = (10^{9} c^{−2}) s/cm (CGS) 

Resistivity, ρ 1 Ω·m (SI) = (10^{11} c^{−2}) s (CGS) 

Capacitance, C 1 F (SI) = (10^{−9} c^{2}) cm (CGS) 

Inductance, L 1 H (SI) = (10^{9} c^{−2}) s^{2}/cm (CGS) 

Conversion of SI to CGS Units 
Electric Charge, q 1 C (SI) = (10^{−1} c) Fr (CGS) 

Electric Current, I 1 A (SI) = (10^{−1} c) Fr/s (CGS) 

Electric Potential, φ · V 1 V (SI) = (10^{8} csup>−1) statV (CGS) 

Electric Field, E 1 V/m (SI) = (10^{6} c^{−1}) statV/cm (CGS) 

Magnetic Induction, B 1 T (SI) = (10^{4}) Gs (CGS) 

Magnetic Field Strength, H 1 A/m (SI) = (4π 10^{−3}) Oe (CGS) 

Magnetic Dipole Moment, μ 1 A·m² (SI) = (10^{3}) erg/Gs (CGS) 

Magnetic Flux, Φ_{m} 1 Wb (SI) = (10^{8}) Gs·cm^{2} (CGS) 

Resistance, R 1 Ω (SI) = (10^{9} c^{−2}) s/cm (CGS) 

Resistivity, ρ 1 Ω·m (SI) = (10^{11} c^{−2}) s (CGS) 

Capacitance, C 1 F (SI) = (10^{−9} c^{2}) cm (CGS) 

Inductance, L 1 H (SI) = (10^{9} c^{−2}) s^{2}/cm (CGS) 
