Metric units are

units Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television series ''Doctor Who'' * Unit of action, a discrete piece of action (or beat) in a theatrical presentation Music * Unit (album), ...

based on the metre, gram or second and decimal (power of ten) multiples or sub-multiples of these. The most widely used examples are the units of the International System of Units (SI). By extension they include units of

electromagnetism In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of ...

from the CGS and SI units systems, and other units for which use of SI prefixes has become the norm. Other unit systems using metric units include: *

International System of Electrical and Magnetic Units The International System of Electrical and Magnetic Units is an obsolete system of units used for measuring electrical and magnetic quantities. It was proposed as a system of practical international units by unanimous recommendation at the Internati ...

* Metre–tonne–second (MTS) system of units *

MKS system of units The MKS system of units is a physical system of measurement that uses the metre, kilogram, and second (MKS) as base units. It forms the base of the International System of Units (SI), though SI has since been redefined by different fundamental ...

(metre, kilogram, second)

Metric units that are part of the SI

The first group of metric units are those that are at present defined as units within the International System of Units (SI). In its most restrictive interpretation, this is what may be meant when the term ''metric unit'' is used. The SI defines 30 named units and associated symbols: * The unit one (1) is the unit of a

quantity of dimension one A dimensionless quantity (also known as a bare quantity, pure quantity, or scalar quantity as well as quantity of dimension one) is a quantity to which no physical dimension is assigned, with a corresponding SI unit of measurement of one (or 1) ...

. * The second (s) is the unit of

time Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, ...

. * The

metre The metre (British spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its prefi ...

(m) is the unit of length. * The kilogram (kg) is the unit of

mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different eleme ...

. * The ampere (A) is the unit of electric current. * The

kelvin The kelvin, symbol K, is the primary unit of temperature in the International System of Units (SI), used alongside its prefixed forms and the degree Celsius. It is named after the Belfast-born and University of Glasgow-based engineer and phy ...

(K) is the unit of

thermodynamic temperature Thermodynamic temperature is a quantity defined in thermodynamics as distinct from kinetic theory or statistical mechanics. Historically, thermodynamic temperature was defined by Kelvin in terms of a macroscopic relation between thermodynamic ...

. * The

mole Mole (or Molé) may refer to: Animals * Mole (animal) or "true mole", mammals in the family Talpidae, found in Eurasia and North America * Golden moles, southern African mammals in the family Chrysochloridae, similar to but unrelated to Talpida ...

(mol) is the unit of amount of substance. * The

candela The candela ( or ; symbol: cd) is the unit of luminous intensity in the International System of Units (SI). It measures luminous power per unit solid angle emitted by a light source in a particular direction. Luminous intensity is analogous t ...

(cd) is the unit of

luminous intensity In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human e ...

. * The

hertz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that o ...

(Hz) is equal to one

reciprocal second The inverse second or reciprocal second (s−1) is a unit of frequency, defined as the multiplicative inverse of the second (a unit of time). It is dimensionally equivalent to: * the unit hertz – the SI unit for frequency * the unit radian per s ...

(). * The

radian The radian, denoted by the symbol rad, is the unit of angle in the International System of Units (SI) and is the standard unit of angular measure used in many areas of mathematics. The unit was formerly an SI supplementary unit (before tha ...

(rad) is equal to one (). * The

steradian The steradian (symbol: sr) or square radian is the unit of solid angle in the International System of Units (SI). It is used in three-dimensional geometry, and is analogous to the radian, which quantifies planar angles. Whereas an angle in radian ...

(sr) is equal to one (). * The newton (N) is equal to one kilogram-metre per second squared (). * The pascal (Pa) is equal to one newton per square metre (). * The

joule The joule ( , ; symbol: J) is the unit of energy in the International System of Units (SI). It is equal to the amount of work done when a force of 1 newton displaces a mass through a distance of 1 metre in the direction of the force applie ...

(J) is equal to one newton-metre (). * The

watt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James ...

(W) is equal to one joule per second (). * The coulomb (C) is equal to one ampere second (). * The

volt The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Defin ...

(V) is equal to one joule per coulomb (). * The weber (Wb) is equal to one volt-second (). * The tesla (T) is equal to one weber per square metre (). * The farad (F) is equal to one coulomb per volt (). * The

ohm Ohm (symbol Ω) is a unit of electrical resistance named after Georg Ohm. Ohm or OHM may also refer to: People * Georg Ohm (1789–1854), German physicist and namesake of the term ''ohm'' * Germán Ohm (born 1936), Mexican boxer * Jörg Ohm (b ...

(Ω) is equal to one volt per ampere (). * The siemens (S) is equal to one ampere per volt (). * The

henry Henry may refer to: People *Henry (given name) * Henry (surname) * Henry Lau, Canadian singer and musician who performs under the mononym Henry Royalty * Portuguese royalty ** King-Cardinal Henry, King of Portugal ** Henry, Count of Portugal, ...

(H) is equal to one volt-second per ampere (). * The

degree Celsius Degree may refer to: As a unit of measurement * Degree (angle), a unit of angle measurement ** Degree of geographical latitude ** Degree of geographical longitude * Degree symbol (°), a notation used in science, engineering, and mathematics ...

(°C) is equal to one kelvin (). * The lumen (lm) is equal to one candela-steradian (). * The lux (lx) is equal to one lumen per square metre (). * The

becquerel The becquerel (; symbol: Bq) is the unit of radioactivity in the International System of Units (SI). One becquerel is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. For applications relatin ...

(Bq) is equal to one

(). * The

gray Grey (more common in British English) or gray (more common in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is "without color", because it can be composed o ...

(Gy) is equal to one joule per kilogram (). * The

sievert The sievert (symbol: SvNot be confused with the sverdrup or the svedberg, two non-SI units that sometimes use the same symbol.) is a unit in the International System of Units (SI) intended to represent the stochastic health risk of ionizing rad ...

(Sv) is equal to one joule per kilogram (). * The

katal The katal (symbol: kat) is the unit of catalytic activity in the International System of Units (SI) used for quantifying the catalytic activity of enzymes (that is, measuring the enzymatic activity level in enzyme catalysis) and other catalyst ...

(kat) is equal to one mole per second (). There are twenty-four

metric prefix A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or submultiple of the unit. All metric prefixes used today are decadic. Each prefix has a unique symbol that is prepended to any unit symbol. The pr ...

es that can be combined with any of these units except one (1) and kilogram (kg) to form further units of the SI. For mass, the same prefixes are applied to the gram (g) instead of the kilogram.

Metric units that are not part of the SI

There are several metric systems, most of which have become disused or are still used in only niche disciplines. Systems are listed with named units that are associated with them.

CGS

The

centimetre–gram–second system of units The centimetre–gram–second system of units (abbreviated CGS or cgs) is a variant of the metric system based on the centimetre as the unit of length, the gram as the unit of mass, and the second as the unit of time. All CGS mechanical units ...

(CGS) is based on three base units: centimetre, gram and second. Its subsystems ( CGS-ESU, CGS-EMU and CGS-Gaussian) have different defining equations for their systems of quantities for defining electromagnetic quantities and hence the associated units, with CGS-Gaussian units being selected from each of the other two subsystems. The CGS-to-SI correspondence of electromagnetic units as given was exact prior to the

2019 redefinition of the SI base units In 2019, four of the seven SI base units specified in the International System of Quantities were redefined in terms of natural physical constants, rather than human artifacts such as the standard kilogram. Effective 20 May 2019, the 144th ...

, until which the magnetic constant ''μ''₀ was defined as . As from the redefinition, ''μ''₀ has an inexactly known value when expressed in SI units, with the exactness of the electromagnetic unit correspondence given here being affected accordingly.

CGS nonelectromagnetic units

* The kayser (K) is a unit of

wavenumber In the physical sciences, the wavenumber (also wave number or repetency) is the '' spatial frequency'' of a wave, measured in cycles per unit distance (ordinary wavenumber) or radians per unit distance (angular wavenumber). It is analogous to te ...

equal to (). * The gal (Gal) is a unit of

acceleration In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by t ...

equal to . * The

dyne The dyne (symbol: dyn; ) is a derived unit of force specified in the centimetre–gram–second (CGS) system of units, a predecessor of the modern SI. History The name dyne was first proposed as a CGS unit of force in 1873 by a Committee of ...

(dyn) is a unit of force equal to (). * The

barye The barye (symbol: Ba), or sometimes barad, barrie, bary, baryd, baryed, or barie, is the centimetre–gram–second (CGS) unit of pressure. It is equal to 1 dyne per square centimetre. : = = = = = See also *Pasca ...

(Ba) is a unit of

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

equal to (). * The

erg The erg is a unit of energy equal to 10−7joules (100 nJ). It originated in the Centimetre–gram–second system of units (CGS). It has the symbol ''erg''. The erg is not an SI unit. Its name is derived from (), a Greek word meaning 'work' o ...

(erg) is a unit of

energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of hea ...

equal to (). * The poise (P) is a unit of dynamic viscosity equal to (). * The stokes (St) is a unit of

kinematic viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the int ...

equal to (). * The stilb (sb) is a unit of luminance equal to (). * The

phot A phot (ph) is a photometric unit of illuminance, or luminous flux through an area. It is not an SI unit but rather is associated with the older centimetre–gram–second system of units. The name was coined by André Blondel in 1921.Parry Moo ...

(ph) is a unit of

illuminance In photometry (optics), photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate w ...

equal to (). * The rayl is a unit of specific acoustic impedance, equal to 1 dyn⋅s⋅cm⁻³.

CGS-ESU electromagnetic units

* The statwatt (statW) is a unit of

power Power most often refers to: * Power (physics), meaning "rate of doing work" ** Engine power, the power put out by an engine ** Electric power * Power (social and political), the ability to influence people or events ** Abusive power Power may a ...

equal to , which is equal to . * The

statcoulomb The franklin (Fr) or statcoulomb (statC) electrostatic unit of charge (esu) is the physical unit for electrical charge used in the cgs-esu and Gaussian units. It is a derived unit given by : 1 statC = 1 dyn1/2⋅cm = 1 cm3/2⋅g1/2⋅s−1. Tha ...

(statC) or

franklin Franklin may refer to: People * Franklin (given name) * Franklin (surname) * Franklin (class), a member of a historical English social class Places Australia * Franklin, Tasmania, a township * Division of Franklin, federal electoral d ...

(Fr) is a unit of

electric charge Electric charge is the physical property of matter that causes charged matter to experience a force when placed in an electromagnetic field. Electric charge can be ''positive'' or ''negative'' (commonly carried by protons and electrons respe ...

equal to , corresponding to ~. * The statampere (statA) is a unit of electric current equal to , corresponding to ~. * The

statvolt The statvolt is a unit of voltage and electrical potential used in the CGS-ESU and gaussian systems of units. In terms of its relation to the SI units, one statvolt corresponds to exactly , i.e. to 299.792458 volts. The statvolt is also ...

(statV) is a unit of

electric potential difference Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...

equal to , corresponding to . * The statohm is a unit of

electric resistance The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels ...

equal to , corresponding to ~. * The statsiemens or statmho is a unit of

electric conductance The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallel ...

equal to , corresponding to ~. * The stathenry is a unit of electric inductance equal to , corresponding to ~. * The statfarad (statF) is a unit of electric capacitance equal to , corresponding to ~. * The statdaraf (statD) is a unit of electric elastance equal to 1/statF. * The statweber is a unit of magnetic flux, corresponding to . * The stattesla is a unit of

magnetic flux density A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

equal to , corresponding to .

CGS-EMU electromagnetic units

* The abwatt (abW) is a unit of

equal to , which is equal to . * The

abcoulomb The abcoulomb (abC or aC) or electromagnetic unit of charge (emu of charge) is the derived physical unit of electric charge in the cgs-emu system of units. One abcoulomb is equal to ten coulombs. The name "abcoulomb" was introduced by Kennelly ...

(abC) is a unit of

equal to , corresponding to . * The

abampere The abampere (abA), also called the biot (Bi) after Jean-Baptiste Biot, is the derived electromagnetic unit of electric current in the emu-cgs system of units (electromagnetic cgs). One abampere corresponds to ten amperes in the SI system of ...

(abA) or biot (Bi) is a unit of electric current, corresponding to . * The

abvolt The abvolt (abV) is the unit of potential difference in the CGS-EMU system of units. It corresponds to in the SI system and 1/ statvolt ≈ in the CGS-ESU system. A potential difference of 1 abV will drive a current of one abampere through ...

(abV) is a unit of

, corresponding to . * The

abohm The abohm is the derived unit of electrical resistance in the emu-cgs ''(centimeter-gram-second)'' system of units (emu stands for "electromagnetic units"). One abohm corresponds to 10−9 ohms in the SI system of units, which is a nanoohm. ...

(abΩ) is a unit of

, corresponding to . * The abmho is a unit of

, corresponding to . * The

abhenry The abhenry is the CGS (centimetre–gram–second) electromagnetic unit of inductance, corresponding to one billionth of a henry Henry may refer to: People *Henry (given name) * Henry (surname) * Henry Lau, Canadian singer and musician who p ...

is a unit of electric inductance, corresponding to . * The abfarad (abF) is a unit of electric capacitance, corresponding to . * The gilbert (Gb) is a unit of

magnetomotive force In physics, the magnetomotive force (mmf) is a quantity appearing in the equation for the magnetic flux in a magnetic circuit, often called Ohm's law for magnetic circuits. It is the property of certain substances or phenomena that give rise to ...

equal to one biot-turn, corresponding to (10/4π) A = . * The

oersted The oersted (symbol Oe) is the coherent derived unit of the auxiliary magnetic field H in the centimetre–gram–second system of units (CGS). It is equivalent to 1 dyne per maxwell. Difference between CGS and SI systems In the CGS system, ...

(Oe) is a unit of

magnetic field strength A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

equal to , corresponding to (1000/4π) A/m = . * The maxwell (Mx) is a unit of magnetic flux, corresponding to . * The

gauss Johann Carl Friedrich Gauss (; german: Gauß ; la, Carolus Fridericus Gauss; 30 April 177723 February 1855) was a German mathematician and physicist who made significant contributions to many fields in mathematics and science. Sometimes refer ...

(G) is a unit of

, corresponding to .

CGS-Gaussian electromagnetic units

* The

(Fr) is a unit of

equal to , corresponding to ~. * The

(Oe) is a unit of

equal to , corresponding to ~. * The maxwell (Mx) is a unit of magnetic flux, corresponding to . * The

(G) is a unit of

, corresponding to .

MTS

* The

tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...

(t) is a unit of

equal to . * The

sthène The sthène (; symbol sn), sometimes spelled (or misspelled) sthéne or sthene (from grc, σθένος, sthénos, force), is an obsolete unit of force (physics), force or thrust in the metre–tonne–second system of units (mts) introduced in Fra ...

(sn) is a unit of force equal to . * The pièze (pz) is a unit of

equal to .

MKSA

* The

cycle per second The cycle per second is a once-common English name for the unit of frequency now known as the hertz (Hz). The plural form was typically used, often written cycles per second, cycles/second, c.p.s., c/s, or, ambiguously, just cycles (Cy./Cyc.). The ...

(cps or cyc/s) is a unit of

frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...

equal to . * The MKS rayl is a unit of

acoustic impedance Acoustic impedance and specific acoustic impedance are measures of the opposition that a system presents to the acoustic flow resulting from an acoustic pressure applied to the system. The SI unit of acoustic impedance is the pascal-second per cu ...

equal to . * The mho (℧) is a unit of

equal to .

MKpS units

* The

kilogram-force The kilogram-force (kgf or kgF), or kilopond (kp, from la, pondus, lit=weight), is a non-standard gravitational metric unit of force. It does not comply with the International System of Units (SI) and is deprecated for most uses. The kilogram- ...

(kgf), also

kilopond The kilogram-force (kgf or kgF), or kilopond (kp, from la, pondus, lit=weight), is a non-standard gravitational metric unit of force. It does not comply with the International System of Units (SI) and is deprecated for most uses. The kilogram-f ...

(kp), is a unit of force (). * The hyl is a unit of

equal to (). * The

poncelet The poncelet (symbol p) is an obsolete unit of power, once used in France and replaced by (ch, metric horsepower). The unit was named after Jean-Victor Poncelet.François Cardarelli, ''Encyclopaedia of Scientific Units, Weights and Measures: The ...

(p) is a unit of

equal to (). * The

technical atmosphere Technical may refer to: * Technical (vehicle), an improvised fighting vehicle * Technical analysis, a discipline for forecasting the future direction of prices through the study of past market data * Technical drawing, showing how something is co ...

(at) is a (non-coherent) unit of

equal to ().

Other metric units

Length

* The fermi is a unit of distance used in

nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies the ...

equal to . * The

angstrom The angstromEntry "angstrom" in the Oxford online dictionary. Retrieved on 2019-03-02 from https://en.oxforddictionaries.com/definition/angstrom.Entry "angstrom" in the Merriam-Webster online dictionary. Retrieved on 2019-03-02 from https://www.m ...

(symbol Å) is a unit of distance used in chemistry and atomic physics equal to . * The

micron The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Un ...

(μ) is a unit of distance equal to one

micrometre The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

(). * The basic module (M) is a unit of distance equal to one hundred millimetres (). * The

myriametre The following are examples of orders of magnitude for different lengths. __TOC__ Overview Detailed list To help compare different orders of magnitude, the following list describes various lengths between 1.6 \times 10^ metres and 10 ...

(mym) is a unit of distance equal to ten kilometres (). * The

hebdometre Hebdo- (symbol H) is an obsolete decimal metric prefix equal to 107. It is derived from the Greek ''hebdοmos'' ( el, ἕβδομος) meaning ''seventh''. The definition of one ''hebdomometre'' or ''hebdometre'' as was originally proposed by R ...

is a unit of distance equal to ten megametres (). * The spat (S) is a unit of distance equal to one terametre ().

Area

* The shed is a unit of area used in nuclear physics equal to 10⁻²⁴

barn A barn is an agricultural building usually on farms and used for various purposes. In North America, a barn refers to structures that house livestock, including cattle and horses, as well as equipment and fodder, and often grain.Alle ...

s (100 rm² = 10⁻⁵² m²). * The

outhouse An outhouse is a small structure, separate from a main building, which covers a toilet. This is typically either a pit latrine or a bucket toilet, but other forms of dry (non-flushing) toilets may be encountered. The term may also be used ...

is a unit of area used in nuclear physics equal to 10⁻⁶ barns (100 am² = 10⁻³⁴ m²). * The

(b) is a unit of area used in nuclear physics equal to one hundred femtometres squared (100 fm² = 10⁻²⁸ m²). * The are (a) is a unit of area equal to . * The

decare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is a ...

(daa) is a unit of area equal to . * The

hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100- metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is ...

(ha) is a unit of area equal to .

Volume

* The

lambda Lambda (}, ''lám(b)da'') is the 11th letter of the Greek alphabet, representing the voiced alveolar lateral approximant . In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoenician Lamed . Lambda gave ri ...

(λ) is a unit of volume equal to one cubic millimetre (1 mm³). * The

litre The litre (international spelling) or liter (American English spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metre (m3 ...

(symbol l or L) is a unit of volume equal to one cubic

decimetre The decimetre (symbol dm) or decimeter (American English) is a unit of length in the International System of Units (SI), equal to one tenth of a metre, ten centimetres, 100 millimetres or 3.937 inches. The common non-SI metric unit of volume, ...

(1 dm³). * The stere (st) is a unit of volume equal to .

Reciprocal length

* The dioptre is a unit of

optical power In optics, optical power (also referred to as dioptric power, refractive power, focusing power, or convergence power) is the degree to which a lens, mirror, or other optical system converges or diverges light. It is equal to the reciprocal of the ...

equal to one

reciprocal metre Reciprocal length or inverse length is a quantity or measurement used in several branches of science and mathematics. As the reciprocal of length, common units used for this measurement include the reciprocal metre or inverse metre (symbol: m− ...

().

Time

* The

svedberg A Svedberg unit or svedberg (symbol S, sometimes Sv) is a non- SI metric unit for sedimentation coefficients. The Svedberg unit offers a measure of a particle's size indirectly based on its sedimentation rate under acceleration (i.e. how fast a ...

(S or Sv) is a unit of time used in chemistry equal to one hundred femtoseconds (). * The shake is a unit of time used in nuclear physics equal to ten

nanosecond A nanosecond (ns) is a unit of time in the International System of Units (SI) equal to one billionth of a second, that is, of a second, or 10 seconds. The term combines the SI prefix ''nano-'' indicating a 1 billionth submultiple of an SI unit ( ...

s (). * The sigma is a unit of time equal to one

microsecond A microsecond is a unit of time in the International System of Units (SI) equal to one millionth (0.000001 or 10−6 or ) of a second. Its symbol is μs, sometimes simplified to us when Unicode is not available. A microsecond is equal to 1000 ...

(). * The jiffy is sometimes used to mean a unit of time of .

Reciprocal time

* The

fresnel Augustin-Jean Fresnel (10 May 1788 – 14 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Newton's corpuscular the ...

is a unit of

equal to .

Reciprocal time squared

* The eotvos (E) is a unit of

gravitational gradient Gravity gradiometry is the study and measurement of variations ( anomalies) in the Earth's gravity field. The gravity gradient tensor is the spatial rate of change of gravitational acceleration; as acceleration is a vector quantity, with magnitu ...

equal to ().

Speed

* The benz is a unit of

speed In everyday use and in kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (ma ...

equal to one metre per second (1 m/s).

Acceleration

* The leo is a unit of acceleration equal to .

Flow rate

* The

sverdrup In oceanography, the sverdrup (symbol: Sv) is a non- SI metric unit of volumetric flow rate, with equal to . It is equivalent to the SI derived unit cubic hectometer per second (symbol: hm3/s or hm3⋅s−1): 1 Sv is equal to 1 hm3/s. It is u ...

(Sv) is a unit of volume flow rate equal to one million metres cubed per second (10⁶ m³/s).Aldersey-Williams, 2016
/ref>

Mass

* The undecimogramme is a unit of

equal to ten picograms (10 pg). * The gamma (γ) is a unit of

equal to one microgram (1 μg). * The gravet is a unit of

equal to one gram (1 g). * The

grave A grave is a location where a dead body (typically that of a human, although sometimes that of an animal) is buried or interred after a funeral. Graves are usually located in special areas set aside for the purpose of burial, such as grav ...

is a unit of

equal to one kilogram (1 kg). * The

bar Bar or BAR may refer to: Food and drink * Bar (establishment), selling alcoholic beverages * Candy bar * Chocolate bar Science and technology * Bar (river morphology), a deposit of sediment * Bar (tropical cyclone), a layer of cloud * Bar (u ...

is a unit of

equal to one megagram (1 Mg).

Linear mass density

* The

tex Tex may refer to: People and fictional characters * Tex (nickname), a list of people and fictional characters with the nickname * Joe Tex (1933–1982), stage name of American soul singer Joseph Arrington Jr. Entertainment * ''Tex'', the Italian ...

(tex) is a unit of

linear mass density Linear density is the measure of a quantity of any characteristic value per unit of length. Linear mass density (titer in textile engineering, the amount of mass per unit length) and linear charge density (the amount of electric charge per unit ...

equal to one gram per kilometre (1 g/km). * The number metric (Nm) is equal to 1000 metres per kilogram (1 km/kg).

Pressure

* The

metre sea water The metre (or meter) sea water (msw) is a metric unit of pressure used in underwater diving. It is defined as one tenth of a bar. The unit used in the US is the foot sea water (fsw), based on standard gravity and a sea-water density of 64&nb ...

(msw) is a unit of

defined as 0.1

, which is equal to . * The bar (bar) is a unit of

equal to .

Energy

* The foe is a unit of

equal to ().

Viscosity

* The

poiseuille The poiseuille (symbol Pl) has been proposed as a derived SI unit of dynamic viscosity, named after the French physicist Jean Léonard Marie Poiseuille (1797–1869). In practice the unit has never been widely accepted and most international s ...

is a unit of dynamic viscosity equal to one pascal-second ().

Electrical

* The

Siemens mercury unit The Siemens mercury unit is an obsolete unit of electrical resistance. It was defined by Werner von Siemens in 1860 as the resistance of a mercury column with a length of one metre The metre (British spelling) or meter (American spelling ...

is a unit of

, corresponding to ~. * The gamma (γ) a unit of

, corresponding to . * The

debye The debye (symbol: D) (; ) is a CGS unit (a non- SI metric unit) of electric dipole momentTwo equal and opposite charges separated by some distance constitute an electric dipole. This dipole possesses an electric dipole moment whose value is g ...

(D) is a unit of electric dipole moment equal to , corresponding to ~. * The buckingham (B) is a unit of electric

quadrupole moment A quadrupole or quadrapole is one of a sequence of configurations of things like electric charge or current, or gravitational mass that can exist in ideal form, but it is usually just part of a multipole expansion of a more complex structure ref ...

equal to .

Electromagnetic radiation

* The

jansky The jansky (symbol Jy, plural ''janskys'') is a non- SI unit of spectral flux density, or spectral irradiance, used especially in radio astronomy. It is equivalent to 10−26 watts per square metre per hertz. The ''flux density'' or ''monoch ...

(Jy) is a unit of

spectral irradiance In radiometry, irradiance is the radiant flux ''received'' by a ''surface'' per unit area. The SI unit of irradiance is the watt per square metre (W⋅m−2). The CGS unit erg per square centimetre per second (erg⋅cm−2⋅s−1) is often used ...

equal to 10⁻²⁶ W⋅m⁻²⋅Hz⁻¹ (). * The solar flux unit is a unit of

equal to 10⁻²² W⋅m⁻²⋅Hz⁻¹ (). * The

nox In atmospheric chemistry, is shorthand for nitric oxide () and nitrogen dioxide (), the nitrogen oxides that are most relevant for air pollution. These gases contribute to the formation of smog and acid rain, as well as affecting tropo ...

(nx) is a unit of

equal to 1 millilux (). * The nit (nt) is a unit of luminance equal to one

per metre squared (). * The lambert (L) is a unit of luminance equal to 10⁴/π cd⋅m⁻². * The lumerg is a unit of

luminous energy In photometry, luminous energy is the perceived energy of light. This is sometimes called the quantity of light.talbot Talbot was an automobile marque introduced in 1902 by English-French company Clément-Talbot. The founders, Charles Chetwynd-Talbot, 20th Earl of Shrewsbury and Adolphe Clément-Bayard, reduced their financial interests in their Clément-Talbot ...

(T) is a unit of

luminous energy In photometry, luminous energy is the perceived energy of light. This is sometimes called the quantity of light.einstein (E) is a unit of

amount Quantity or amount is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value multiple of a unit ...

photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they a ...

s, equal to one

(1 mol) of photons. * The rayleigh (R) is a unit of photon flux rate density equal to 10¹⁰ m⁻²⋅s⁻¹ (10⁴ mm⁻²⋅s⁻¹).

Radioactivity

* The rad (rad) is a unit of absorbed dose equal to . * The roentgen equivalent man (rem) is a unit of

equivalent dose Equivalent dose is a dose quantity '' H '' representing the stochastic health effects of low levels of ionizing radiation on the human body which represents the probability of radiation-induced cancer and genetic damage. It is derived from the p ...

equal to . * The rutherford (Rd) is a unit of radioactivity defined as one million decays per second ().

Concentration

* The molar (M) is equal to one mole per litre ().

Nonmetric units

Hybrid units

Some nonmetric units arose as a combination of a nonmetric quantity combined with a metric unit. Examples include:

Metric unit combined with a unit permitted alongside the SI

* The ampere hour is a unit of electric charge equal to . * The

watt hour A kilowatt-hour ( unit symbol: kW⋅h or kW h; commonly written as kWh) is a unit of energy: one kilowatt of power for one hour. In terms of SI derived units with special names, it equals 3.6 megajoules (MJ). Kilowatt-hours are a common bi ...

(W⋅h) is equal to . * The watt hour per day (W⋅h/d) is a unit of power equal to 3.6 kJ/(24 h) = 1/24 W. * The

enzyme unit The enzyme unit, or international unit for enzyme (symbol U, sometimes also IU) is a unit of enzyme's catalytic activity. 1 U (μmol/min) is defined as the amount of the enzyme that catalyzes the conversion of one micromole of substrate per min ...

(U) is equal to one micromole per minute (50/3 nkat).

Other combinations

* The normal litre per minute (NLPM) is approximately equal to (0.001/60) m³/s. * The

standard litre per minute The standard liter per minute (SLM or SLPM) is a unit of volumetric flow rate of a gas at standard conditions for temperature and pressure (STP), which is most commonly practiced in the United States, whereas European practice revolves around the ...

(SLPM) is approximately equal to (0.001/60) m³/s. * The

centimetre of water A centimetre or millimetre of water (US spelling ''centimeter'' or ''millimeter of water'') are less commonly used measures of pressure derived from pressure head. Centimetre of water A ''centimetre of water'' (US spelling ''centimeter of water ...

(cmH₂O) is approximately . * The

millimetre of mercury A millimetre of mercury is a manometric unit of pressure, formerly defined as the extra pressure generated by a column of mercury one millimetre high, and currently defined as exactly pascals. It is denoted mmHg or mm Hg. Although not an ...

(mmHg) is approximately . * The

torr The torr (symbol: Torr) is a unit of pressure based on an absolute scale, defined as exactly of a standard atmosphere (). Thus one torr is exactly (≈ ). Historically, one torr was intended to be the same as one " millimeter of merc ...

(Torr) is approximately 133.3224 pascals. * The centimetre of mercury (cmHg) is approximately . * The

electronvolt In physics, an electronvolt (symbol eV, also written electron-volt and electron volt) is the measure of an amount of kinetic energy gained by a single electron accelerating from rest through an electric potential difference of one volt in vacuum ...

(eV) is equal to = . * The calorie (cal) is . * The

langley Langley may refer to: People * Langley (surname), a common English surname, including a list of notable people with the name * Dawn Langley Simmons (1922–2000), English author and biographer * Elizabeth Langley (born 1933), Canadian perfor ...

(Ly) is a unit of energy density equal to 1 calorie per square centimetre (). * The darcy (d) is a unit of permeability approximately equal to ().

Traditional units standardized in terms of metric units

Further traditional units were standardized by defining them in terms of metric units, such as the imperial inch, almost always retaining their original name, and replaced the units as traditionally defined. Nonmetric units that arose as approximations to traditional units that were adjusted for convenient conversion to metric units were typically named as for the traditional unit but qualified with the word "metric". The corresponding original traditional usually remained in use alongside the corresponding "metric" version.

Units equal to an SI unit multiplied by an integer power of 10, and multiplied or divided by 1, 2, 3 or 4

* The neper (Np) is a unit of logarithmic ratio equal to 1. * The percent (%) is equal to one part in a hundred (0.01). * The

permille Per mille (from Latin , "in each thousand") is an expression that means parts per thousand. Other recognised spellings include per mil, per mill, permil, permill, or permille. The associated sign is written , which looks like a percent sig ...

(‰) is equal to one part in a thousand (0.001). * The

permyriad A basis point (often abbreviated as bp, often pronounced as "bip" or "beep") is one hundredth of 1 percentage point. The related term '' permyriad'' means one hundredth of 1 percent. Changes of interest rates are often stated in basis points. If ...

(‱) is equal to one part in ten thousand (). * The

part per million In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they ...

(ppm) is equal to one part in a million (). * The

part per billion In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they ...

(ppb) is equal to one part in a billion (). * The part per trillion (ppt) is equal to one part in a trillion (). * The part per quadrillion (ppq) is equal to one part in a quadrillion (). * The metric inch is equal to twenty five millimetres (). * The cun is equal to one tenth of a chi (approximately 33.3333 mm). * The

metric foot ISO 2848 (''Building construction – Modular coordination – Principles and rules)'' is an international standard for the construction industry that describes the aims of modular coordination and gives the rules to be used in establishing the di ...

is equal to three hundred millimetres (). * The chi is equal to one third of a metre (approximately 333.333 mm). * The metric lieue is equal to four kilometres (). * The

Scandinavian mile A Scandinavian mile (Norwegian and sv, mil, [], like "meal") is a unit of length common in Norway and Sweden, but not Denmark. Today, it is standardised as 1 being , but it had different values in the past. The word is derived from the same ...

(''mil'') is equal to ten kilometres (). * The metric dunam is equal to one thousand metres squared (). * The

stremma The stremma ( stremmata; el, στρέμμα, ''strémma'') is a Greek unit of land area equal to 1,000 square metres. Historically, stremmata were not standardized, and may have been anywhere from . History The ancient Greek equivalent was the s ...

is equal to one thousand metres squared (1000 m²). * The '' food labeling ounce'' is equal to 30 cm³. * The

metric cup The cup is a cooking measure of volume, commonly associated with cooking and serving sizes. In the US, it is traditionally equal to . Because actual drinking cups may differ greatly from the size of this unit, standard measuring cups may be use ...

is equal to . * The metric carat (ct) is equal to . * The li is equal to one ten-thousandth of a jin (50 mg). * The

fen A fen is a type of peat-accumulating wetland fed by mineral-rich Groundwater, ground or surface water. It is one of the main types of wetlands along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as ...

is equal to one thousandth of a jin (500 mg). * The qian is equal to one hundredth of a jin (5 g). * The liang (or tael) is equal to one tenth of a jin (50 g). * The metric pound is equal to . * The jin (or catty) is equal to 500 g. * The

dan Dan or DAN may refer to: People * Dan (name), including a list of people with the name ** Dan (king), several kings of Denmark * Dan people, an ethnic group located in West Africa **Dan language, a Mande language spoken primarily in Côte d'Ivoi ...

is equal to one hundred jin (50 kg). * The metric quintal (q) is equal to one hundred kilograms (). * The donkey power is equal to 250 W.

Other units

* The mo is equal to one ten-thousandth of a shaku (approximately 0.0303030 mm). * The rin is equal to one thousandth of a shaku (approximately 0.303030 mm). * The bu is equal to one hundredth of a shaku (approximately 3.03030 mm). * The

sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

is equal to one tenth of a shaku (approximately 30.3030 mm). * The shaku is equal to 10/33 m (approximately 303.030 mm). * The jo is equal to ten shaku (approximately 3030.30 mm). * The metric mile is equal to . * The

tsubo A ''pyeong'' (abbreviationpy) is a Korean unit of area and floorspace, equal to a square '' kan'' or 36square Korean feet. The ''ping'' and ''tsubo'' are its equivalent Taiwanese and Japanese units, similarly based on a square '' bu'' ( ja:步) ...

is equal to 400/121 metres squared (approximately 3.306 m²). * The

sho Sho, Shō or SHO may refer to: Music * ''Shō'' (instrument) (笙), a Japanese wind instrument * ''Kane'' (instrument) (鉦), a Japanese percussion instrument * Sho?, a Dubai rock band People * Shō (given name), including ''Sho'' * Shō (su ...

is equal to 2401/1331 litres (approximately 1.804 dm³). * The hyakume is equal to one tenth of a kan (375 g). * The kan is equal to 15/4 kilograms (3.75 kg). * The

metric horsepower Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the ...

is equal to (approximately 735.499 W).

Notes

References

{{Reflist Metric system