List of metric units

The centimetre–gram–second system of 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, until which the magnetic constant μ₀ was defined as 4π×10⁻⁷ N⋅A⁻². As from the redefinition, μ₀ has an inexactly known value when expressed in SI units, with the exactness of the electromagnetic unit correspondence given here being affected accordingly.

• The kayser (K) is a unit of wavenumber equal to 1 cm⁻¹ (100 m⁻¹).
• The gal (Gal) is a unit of acceleration equal to 1 cm/s².[3]
• The dyne (dyn) is a unit of force equal to 1 g⋅cm⋅s⁻² (10 μN).[3]
• The barye (Ba) is a unit of pressure equal to 1 dyn⋅cm⁻² (100 mPa).
• The erg (erg) is a unit of energy equal to 1 dyn⋅cm (100 nJ).[3]
• The poise (P) is a unit of dynamic viscosity equal to 1 Ba⋅s (100 mPa⋅s).[3]
• The stokes (St) is a unit of kinematic viscosity equal to 1 cm²⋅s⁻¹ (100 mm²⋅s⁻¹).[3]
• The stilb (sb) is a unit of luminance equal to 1 cd⋅cm⁻² (10 kcd⋅m⁻²).[4]
• The phot (ph) is a unit of illuminance equal to 1 lm⋅cm⁻² (10 klx).[3]
• The rayl is a unit of specific acoustic impedance, equal to 1 dyn⋅s⋅cm⁻³.[5]

• The statwatt (statW) is a unit of power equal to 1 statV⋅statA, which is equal to 100 nW.[6]
• The statcoulomb (statC) or franklin (Fr) is a unit of electric charge equal to 1 dyn^1/2⋅cm, corresponding to ~333.564 pC.
• The statampere (statA) is a unit of electric current equal to 1 statC/s, corresponding to ~333.564 pA.
• The statvolt (statV) is a unit of electric potential difference equal to 1 erg/statC, corresponding to 299.792458 V.
• The statohm is a unit of electric resistance equal to 1 statV/statA, corresponding to ~898.7551787 GΩ.
• The statsiemens or statmho is a unit of electric conductance equal to 1 statA/statV, corresponding to ~1.112646 pS.[6]
• The stathenry is a unit of electric inductance equal to 1 statV·s/statA, corresponding to ~898.7551787 GH.[7][6][lower-alpha 1]
• The statfarad (statF) is a unit of electric capacitance equal to 1 statC/statV, corresponding to ~1.112646 pF.[6]
• The statdaraf (statD) is a unit of electric elastance equal to 1/statF.[6]
• The statweber is a unit of magnetic flux, corresponding to 299.792458 Wb.[7][6]
• The stattesla is a unit of magnetic flux density equal to 1 statWb⋅cm⁻², corresponding to 2.99792458 MT.[7]

• The abwatt (abW) is a unit of power equal to 1 abV⋅abA, which is equal to 100 nW.[6]
• The abcoulomb (abC) is a unit of electric charge equal to 1 abA⋅s, corresponding to 10 C.
• The abampere (abA) or biot (Bi) is a unit of electric current, corresponding to 10 A.
• The abvolt (abV) is a unit of electric potential difference, corresponding to 10 nV.
• The abohm (abΩ) is a unit of electric resistance, corresponding to 1 nΩ.
• The abmho is a unit of electric conductance, corresponding to 1 GS.
• The abhenry is a unit of electric inductance, corresponding to 1 nH.
• The abfarad (abF) is a unit of electric capacitance, corresponding to 1 GF.
• The gilbert (Gb) is a unit of magnetomotive force equal to one biot-turn, corresponding to (10/4π) A = 0.7957747... A.
• The oersted (Oe) is a unit of magnetic field strength equal to 1 dyn^1/2⋅cm⁻¹, corresponding to (1000/4π) A/m = 79.57747... A/m.
• The maxwell (Mx) is a unit of magnetic flux, corresponding to 10 nWb.[4]
• The gauss (G) is a unit of magnetic flux density, corresponding to 100 μT.[4]

• The franklin (Fr) is a unit of electric charge equal to 1 statC, corresponding to ~333.564 pC.
• The oersted (Oe) is a unit of magnetic field strength equal to 1 dyn^1/2⋅cm⁻¹, corresponding to ~79.57747 A/m.
• The maxwell (Mx) is a unit of magnetic flux, corresponding to 10 nWb.[4]
• The gauss (G) is a unit of magnetic flux density, corresponding to 100 μT.[4]

• The tonne (t) is a unit of mass equal to 1 Mg.
• The sthène (sn) is a unit of force equal to 1 kN.
• The pièze (pz) is a unit of pressure equal to 1 kPa.

• The cycle per second (cps or cyc/s) is a unit of frequency equal to 1 Hz.
• The MKS rayl is a unit of acoustic impedance equal to 1 Pa⋅s/m.
• The mho (℧) is a unit of electric conductance equal to 1 S.

• The kilogram-force (kgf), also kilopond (kp), is a unit of force (9.80665 N).[8]
• The hyl is a unit of mass equal to 1 kgf⋅m⁻¹⋅s² (9.80665 kg).
• The poncelet (p) is a unit of power equal to 1 kgf⋅m⋅s⁻¹ (980.665 W).
• The technical atmosphere (at) is a (non-coherent) unit of pressure equal to 1 kgf⋅cm⁻² (98066.5 Pa).

• The fermi is a unit of distance used in nuclear physics equal to 1 fm.[9]
• The angstrom (symbol Å) is a unit of distance used in chemistry and atomic physics equal to 100 pm.
• The micron (μ) is a unit of distance equal to one micrometre (1 μm).
• The basic module (M) is a unit of distance equal to one hundred millimetres (100 mm).
• The myriametre (mym) is a unit of distance equal to ten kilometres (10 km).
• The hebdometre is a unit of distance equal to ten megametres (10 Mm).
• The spat (S) is a unit of distance equal to one terametre (1 Tm).

• The shed is a unit of area used in nuclear physics equal to 10⁻²⁴ barns (100 rm² = 10⁻⁵² m²).
• The outhouse is a unit of area used in nuclear physics equal to 10⁻⁶ barns (100 am² = 10⁻³⁴ m²).
• The barn (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 100 m².
• The decare (daa) is a unit of area equal to 1000 m².
• The hectare (ha) is a unit of area equal to 10000 m².

• The lambda (λ) is a unit of volume equal to one cubic millimetre (1 mm³).
• The litre (symbol l or L) is a unit of volume equal to one cubic decimetre (1 dm³).
• The stere (st) is a unit of volume equal to 1 m³.

• The dioptre is a unit of optical power equal to one reciprocal metre (1 m⁻¹).

• The svedberg (S or Sv) is a unit of time used in chemistry equal to one hundred femtoseconds (100 fs).
• The shake is a unit of time used in nuclear physics equal to ten nanoseconds (10 ns).
• The sigma is a unit of time equal to one microsecond (1 μs).
• The jiffy is sometimes used to mean a unit of time of 10 ms.

• The fresnel is a unit of frequency equal to 1 THz.

• The eotvos (E) is a unit of gravitational gradient equal to 10⁻⁹ Gal/cm (10⁻⁹ s⁻²).

• The benz is a unit of speed equal to one metre per second (1 m/s).

• The leo is a unit of acceleration equal to 10 m⋅s⁻².[10]

• The sverdrup (Sv) is a unit of volume flow rate equal to one million metres cubed per second (10⁶ m³/s).[11]

• The undecimogramme is a unit of mass equal to ten picograms (10 pg).
• The gamma (γ) is a unit of mass equal to one microgram (1 μg).
• The gravet is a unit of mass equal to one gram (1 g).
• The grave is a unit of mass equal to one kilogram (1 kg).
• The bar is a unit of mass equal to one megagram (1 Mg).

• The tex (tex) is a unit of linear mass density equal to one gram per kilometre (1 g/km).[12]
• The number metric (Nm) is equal to 1000 metres per kilogram (1 km/kg).

• The metre sea water (msw) is a unit of pressure defined as 0.1 bar, which is equal to 10 kPa.
• The bar (bar) is a unit of pressure equal to 100 kPa.

• The foe is a unit of energy equal to 10⁵¹ erg (10⁴⁴ J).

• The poiseuille is a unit of dynamic viscosity equal to one pascal-second (1 Pa⋅s).[13]

• The Siemens mercury unit is a unit of electric resistance, corresponding to ~0.953 Ω.
• The gamma (γ) a unit of magnetic flux density, corresponding to 1 nT.[14]
• The debye (D) is a unit of electric dipole moment equal to 10⁻¹⁸ statC⋅cm, corresponding to ~3.33564 qC⋅m.
• The buckingham (B) is a unit of electric quadrupole moment equal to 10⁻²⁶ statC⋅cm².

• The jansky (Jy) is a unit of spectral irradiance equal to 10⁻²⁶ W⋅m⁻²⋅Hz⁻¹ (10 rW⋅m⁻²⋅Hz⁻¹).
• The solar flux unit is a unit of spectral irradiance equal to 10⁻²² W⋅m⁻²⋅Hz⁻¹ (100 yW⋅m⁻²⋅Hz⁻¹).
• The nox (nx) is a unit of illuminance equal to 1 millilux (1 mlx).
• The nit (nt) is a unit of luminance equal to one candela per metre squared (1 cd⋅m⁻²).
• The lambert (L) is a unit of luminance equal to 10⁴/π cd⋅m⁻².
• The lumerg is a unit of luminous energy equal to 10⁻⁷ lumen-seconds (100 nlm s).
• The talbot (T) is a unit of luminous energy equal to one lumen-second (1 lm⋅s).
• The einstein (E) has two conflicting definitions. The original is a unit of energy, equal to the energy in one mole (1 mol) of photons. The second is a unit of amount of photons, equal to one mole (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).

• The rad (rad) is a unit of absorbed dose equal to 10 mGy.
• The roentgen equivalent man (rem) is a unit of equivalent dose equal to 10 mSv.
• The rutherford (Rd) is a unit of radioactivity defined as one million decays per second (1 MBq).

• The molar (M) is equal to one mole per litre (1 mol/dm³).

• The acoustic ohm is a unit of acoustic impedance equal to 1 Pa·s/m³.

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

• The ampere-hour is a unit of electric charge equal to 3.6 kC.
• The watt-hour (W⋅h) is equal to 3.6 kJ.
• 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 (U) is equal to one micromole per minute (50/3 nkat).

• The normal litre per minute (NLPM) is approximately equal to (0.001/60) m³/s.
• The standard litre per minute (SLPM) is approximately equal to (0.001/60) m³/s.
• The centimetre of water (cmH₂O) is approximately 98.0665 Pa.
• The millimetre of mercury (mmHg) is approximately 133.3224 Pa.
• The torr (Torr) is approximately 133.3224 pascals.
• The centimetre of mercury (cmHg) is approximately 1.333224 kPa.
• The electronvolt (eV) is equal to 1.602176634×10⁻¹⁹ J = 160.2176634 zJ.
• The calorie (cal) is 4.184 J.[lower-alpha 2]
• The langley (Ly) is a unit of energy density equal to 1 calorie per square centimetre (41.84 kJ/m²).
• The darcy (d) is a unit of permeability approximately equal to 9.869233×10⁻¹³ m² (0.9869233 µm²).

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.

• 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 (‰) is equal to one part in a thousand (0.001).
• The permyriad (‱) is equal to one part in ten thousand (0.0001).
• The part per million (ppm) is equal to one part in a million (0.000001).
• The part per billion (ppb) is equal to one part in a billion (0.000000001).
• The part per trillion (ppt) is equal to one part in a trillion (0.000000000001).
• The part per quadrillion (ppq) is equal to one part in a quadrillion (0.000000000000001).

• The metric inch is equal to twenty five millimetres (25 mm).
• The cun is equal to one tenth of a chi (approximately 33.3333 mm).
• The metric foot is equal to three hundred millimetres (300 mm).
• The chi is equal to one third of a metre (approximately 333.333 mm).
• The metric chain is equal to 20 m.
• The metric lieue is equal to four kilometres (4 km).
• The Scandinavian mile (mil) is equal to ten kilometres (10 km).

• The metric dunam is equal to one thousand metres squared (1000 m²).
• The stremma is equal to one thousand metres squared (1000 m²).

• The food labeling ounce is equal to 30 cm³.
• The metric cup is equal to 250 cm³.

• The metric carat (ct) is equal to 200 mg.
• The li is equal to one ten-thousandth of a jin (50 mg).
• The fen 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 500 g.
• The jin (or catty) is equal to 500 g.
• The dan is equal to one hundred jin (50 kg).
• The metric quintal (q) is equal to one hundred kilograms (100 kg).

• The donkey power is equal to 250 W.

• 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 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 1.5 km.

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

• The sho 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 is equal to 75 kgf⋅m/s (approximately 735.499 W).