# List of physical quantities

 Quick reference Ratio size related size extensive state variable intensive state variable Process variable Energy size Field size

This list shows all the important physical quantities  - the SI base quantities and quantities derived from them - in technology and natural sciences, sorted according to areas of knowledge.

The symbols used are largely based on the international standards or those specified by DIN 1304 for German-speaking countries. Several symbols are common for some physical quantities, as this quantity is used in different areas of application.

There are clear standards for correct use and the notation of sizes, units and values .

Physical constants are not listed in the table below.

## SI base quantities and units

Base size Formula symbol Symbol for dimension Base unit Unit symbol
length ${\ displaystyle l \,}$, , , , Etc. ${\ displaystyle s \,}$${\ displaystyle x \,}$${\ displaystyle r \,}$ L. meter ${\ displaystyle \ mathrm {m} \,}$
Dimensions ${\ displaystyle m \,}$ M. kilogram ${\ displaystyle \ mathrm {kg} \,}$
time ${\ displaystyle t \,}$ T second ${\ displaystyle \ mathrm {s} \,}$
electric current ${\ displaystyle I \,}$ I. amp ${\ displaystyle \ mathrm {A} \,}$
absolute temperature (also thermodynamic temperature ) ${\ displaystyle T \,}$ θ Kelvin ${\ displaystyle \ mathrm {K} \,}$
Amount of substance ${\ displaystyle n \,}$ N Mole ${\ displaystyle \ mathrm {mol} \,}$
Light intensity ${\ displaystyle I _ {\ mathrm {V}} \,}$ J Candela ${\ displaystyle \ mathrm {cd} \,}$

## geometry

Size type Physical size Formula symbol Dimen. SI unit Other units comment
flat angle flat angle , angle of rotation ${\ displaystyle \ alpha, \, \ beta, \, \ gamma, \, \ ldots,}$

${\ displaystyle \ varphi, \, \ theta, \, \ ldots}$

Gon (gon, g )
arc minute (′)

Solid angle Solid angle ${\ displaystyle \ Omega, \, \ omega}$ 1 Steradian (sr) Square degree ((°) ²)
length length ${\ displaystyle l \,}$ L. Meter (m)

Ångström (Å)
astronomical unit  (AU)
light year (Lj, ly, lyr)
parsec (pc)
nautical mile (sm)

length width ${\ displaystyle b \,}$ L. Meter (m) Ångström (Å)
length Height , depth ${\ displaystyle h \,}$ L. Meter (m) Ångström (Å)
length Thickness, layer thickness ${\ displaystyle \ sigma, \, d}$ L. Meter (m) Ångström (Å)
length Radius ( radius ), distance ${\ displaystyle r \,}$ L. Meter (m)

Ångström (Å)
astronomical unit (AU)
light year (Lj, ly, lyr)
parsec (pc)

length diameter ${\ displaystyle d, \, D}$ L. Meter (m)

Ångström (Å)
astronomical unit (AU)
light year (Lj, ly, lyr)
parsec (pc)

length Path length, curve length ${\ displaystyle s \,}$ L. Meter (m)

Ångström (Å)
astronomical unit (AU)
light year (Lj, ly, lyr)
parsec (pc)
nautical mile (sm)

surface Area , surface ${\ displaystyle A, \, S}$ L 2 Square meter (m 2 ) Ar (a)
hectare (ha)
surface Cross sectional area ${\ displaystyle S, \, Q}$ L 2 Square meter (m 2 ) Barn (b)
volume Volume , volume ${\ displaystyle V \,}$ L 3 Cubic meter (m 3 ) Liter (l)

## kinematics

Size type Physical size Formula symbol dimension SI unit Other units comment
time Time, time span , duration ${\ displaystyle t \,}$ T Second (s)

Minute (min)
hour (h)
day (d)
year (a)

time Period duration ${\ displaystyle T, \, {\ tau}}$ T Second (s)

Minute (min)
hour (h)
day (d)
year (a)

time Time constant ${\ displaystyle {\ tau}, \, T}$ T Second (s)
speed speed ${\ displaystyle v, \, u, \, w, \, c}$ LT −1 m · s −1 Kilometers per hour (km h −1 )
speed Flow velocity ${\ displaystyle \ omega \,}$ LT −1 m · s −1 Kilometers per hour (km h −1 )
acceleration acceleration ${\ displaystyle a \,}$ LT −2 m · s −2
acceleration local acceleration due to gravity ${\ displaystyle g \,}$ LT −2 m · s −2 gal
shock shock ${\ displaystyle j \,}$ LT −3 m · s −3
frequency Frequency , period frequency ${\ displaystyle f, \, \ nu}$ T −1 Hertz (Hz) s −1
frequency Speed , rotational frequency ${\ displaystyle n, \, f _ {\ mathrm {red}}}$ T −1 s −1 U · s −1
Angular frequency Angular frequency , angular frequency ${\ displaystyle \ omega \,}$ T −1 rad · s −1
Angular velocity Angular velocity ${\ displaystyle \ omega, \, \ Omega}$ T −1 rad · s −1
Angular acceleration Angular acceleration ${\ displaystyle \ alpha \,}$ T −2 rad · s −2
length wavelength ${\ displaystyle \ lambda \,}$ L. Meter (m) Ångström (Å)
viscosity kinematic viscosity ${\ displaystyle \ nu \,}$ L 2 T -1 m 2 s −1 Stokes (St)

## mechanics

Size type Physical size FZ dimension SI unit Other units comment
Dimensions Dimensions ${\ displaystyle m \,}$ M. Kilogram (kg) Gram (g)
ton (t)
metric carat (ct)
force force ${\ displaystyle F \,}$ MLT −2 Newton (N) dyn (dyn)
kilopond (kp)
force Weight force ${\ displaystyle F _ {\ mathrm {G}}, \, G}$ MLT −2 Newton (N) Dyn (dyn)
kilopond (kp)
force friction ${\ displaystyle F _ {\ mathrm {R}} \,}$ MLT −2 Newton (N) Dyn (dyn)
kilopond (kp)
pulse pulse ${\ displaystyle p \,}$ MLT −1 N · s kg m s −1
pulse Impulse ${\ displaystyle S, \, I}$ MLT −1 N · s kg m s −1
Moment of inertia Moment of inertia ${\ displaystyle I, \, J, \, {\ mathit {\ Theta}}}$ ML 2 kg · m²
Torque Torque ( moment of force ) ${\ displaystyle M \,}$ ML 2 T −2 Newton meter (Nm) Dynmeter (dynm)
Kilopondmeter (kpm)
Torque Torsional , restraint moment , bending moment ${\ displaystyle M _ {\ mathrm {T}}, \, T; \, M}$ M L² T −2 Newton meter (Nm)
Angular momentum Angular momentum , twist ${\ displaystyle L \,}$ M L² T −1 kg · m² · s −1 J · s
effect effect ${\ displaystyle S \,}$ ML 2 T −1 kg · m² · s −1 J · s
energy job ${\ displaystyle W, \, E}$ M L² T −2 Joule (J) Newton meter (Nm)
Kilowatt hour (kWh)
Electron volt (eV)
Kilopond meter (kpm)
Erg (erg)
Calorie (cal)
energy energy ${\ displaystyle W, \, E}$ M L² T −2 Joule (J) Newton meter (Nm)
Kilowatt hour (kWh)
Electron volt (eV)
Kilopond meter (kpm)
Erg (erg)
Calorie (cal)
Energy density volumetric energy density ${\ displaystyle \ rho, \, w}$ ML −1 T −2 J m −3
Energy density specific energy ${\ displaystyle \ rho, \, w}$ L 2 T −2 J kg −1
power power ${\ displaystyle P \,}$ ML 2 T −3 Watt (W) VA
kpm s −1
horsepower (PS)
Power density Intensity , area-related power density ${\ displaystyle I, \, S, \, E, \, M, \, q, \, \ psi}$ MT −3 W m −2
Power density volumetric power density ${\ displaystyle \ phi}$ ML −1 T −3 W m −3
Power density specific performance ${\ displaystyle \ rho, \, w}$ L 2 T −3 W kg −1
coefficient Efficiency ${\ displaystyle \ eta \,}$ 1 one
Mass density density ${\ displaystyle \ rho, \, \ rho _ {\ mathrm {m}}}$ M · L −3 kg m −3
Mass occupancy Mass occupancy ${\ displaystyle \ rho _ {\ mathrm {A}}}$ M · L −2 kg m −2
specific volume specific volume ${\ displaystyle v \,}$ M −1 L 3 m 3 kg −1
specific weight specific weight (specific gravity) ${\ displaystyle \ gamma \,}$ M · L −2 · T −2 kg m −2 s −2 N m −3
mechanical tension pressure ${\ displaystyle p \,}$ M · L −1 · T −2 Pascal  (Pa)

Bar  (bar)
physical atmosphere  (atm)
technical atmosphere  (at)
Torr  (Torr)
millimeter mercury column (mm Hg)
meter water column  (mWS)

mechanical tension absolute pressure ${\ displaystyle p _ {\ mathrm {abs}} \,}$ ML −1 T −2 Pascal (Pa) Nm −2
bar (bar)
mechanical tension Air pressure ${\ displaystyle p _ {\ mathrm {amb}} \,}$ ML −1 T −2 Pascal (Pa) Nm −2
bar (bar)
mechanical tension atmospheric pressure difference , overpressure ${\ displaystyle p _ {\ mathrm {e}} \,}$ ML −1 T −2 Pascal (Pa) N · m -2
bar (bar)
mechanical tension Normal stress ( tensile or compressive stress ) ${\ displaystyle \ sigma \,}$ ML −1 T −2 Pascal (Pa) N · m -2
bar (bar)
mechanical tension Shear stress ${\ displaystyle \ tau \,}$ ML −1 T −2 Pascal (Pa) N · m -2
bar (bar)
module modulus of elasticity ${\ displaystyle E \,}$ ML −1 T −2 N m −2
module Shear modulus ${\ displaystyle G \,}$ ML −1 T −2 N m −2
module Compression module ${\ displaystyle K \,}$ ML −1 T −2 N m −2
Spring constant Spring constant ${\ displaystyle D, \, k, \, c}$ MT −2 N m −1
Compressibility Compressibility ${\ displaystyle \ kappa, \, \ chi}$ MT −2 N m −1
coefficient Elongation , relative change in length ${\ displaystyle \ mathrm {\ epsilon \,}}$ 1 one
coefficient Push , shear ${\ displaystyle \ gamma \,}$ 1 one
coefficient Poisson's number ${\ displaystyle \ mu, \, \ nu}$ 1 one
viscosity dynamic viscosity ${\ displaystyle \ eta \,}$ ML −1 T −1 Pa · s Poise (P)
viscosity kinematic viscosity ${\ displaystyle \ nu \,}$ L 2 T −1 m 2 s −1 Stokes (St)
coefficient Reynolds number ${\ displaystyle Re \,}$ 1 one
coefficient Coefficient of friction ${\ displaystyle \ mu, \, f}$ 1 one
Volume flow Volume flow ${\ displaystyle Q \,}$ L 3 T −1 m 3 s −1
Mass flow Mass flow ${\ displaystyle q_ {m}}$ MT −1 kg s −1

## thermodynamics

Size type Physical size Formula symbol dimension SI unit Other units comment
temperature absolute temperature ${\ displaystyle T \,}$ Θ Kelvin (K)
temperature Temperature difference ${\ displaystyle {\ Delta T, \, \ Delta \ vartheta, \, \ Delta t}}$ Θ Kelvin (K) Degree Celsius (° C)
Degree Fahrenheit (° F)
Degree Rankine (° Ra)
Degree (grd.)
temperature Celsius temperature ${\ displaystyle \ vartheta, \, t}$ Θ Degrees Celsius (° C) Kelvin (K)
energy Heat , amount of heat ${\ displaystyle Q \,}$ ML 2 T −2 Joule (J)
energy inner energy ${\ displaystyle U \,}$ ML 2 T −2 Joule (J)
energy thermal energy ${\ displaystyle E _ {\ mathrm {th}} \,}$ ML 2 T −2 Joule (J)
energy chemical potential ${\ displaystyle \ mu \,}$ ML 2 T −2 Joule (J)
energy Enthalpy ${\ displaystyle H \,}$ ML 2 T −2 Joule (J)
power Heat flow ${\ displaystyle {\ mathit {\ Phi}} _ {\ mathrm {th}}, \, {\ mathit {\ Phi}}, \, {\ dot {Q}}}$ ML 2 T −3 Watt (W) J · s −1
Power density Heat flux density ${\ displaystyle {q}, \, {\ dot {q}}}$ MT −3 W m −2
entropy entropy ${\ displaystyle S \,}$ ML 2 T −2 Θ −1 J · K −1
Heat capacity Heat capacity ${\ displaystyle C _ {\ mathrm {th}}, \, C}$ ML 2 T −2 Θ −1 J · K −1
specific heat capacity specific heat capacity ${\ displaystyle c \,}$ L 2 T −2 Θ −1 J K −1 kg −1
Temperature coefficient Coefficient of linear expansion ${\ displaystyle {\ alpha} _ {1} \,}$ Θ −1 K −1
Temperature coefficient Volume expansion coefficient ${\ displaystyle {\ alpha} _ {v}, \, \ gamma}$ Θ −1 K −1
Thermal conductivity Thermal conductivity ${\ displaystyle {\ lambda} \,}$ MLT −3 Θ −1 W K −1 m −1
Temperature coefficient Heat transfer coefficient ${\ displaystyle \ alpha, \, h}$ MT −3 Θ −1 W K −1 m −2
Temperature coefficient Heat transfer coefficient ${\ displaystyle U \,}$ MT −3 Θ −1 W K −1 m −2
Thermal resistance Thermal resistance ${\ displaystyle R \,}$ M −1 T 3 Θ m 2 W K −1
Thermal diffusivity Thermal diffusivity ${\ displaystyle a \,}$ L 2 T −1 m 2 s −1

## Electrodynamics

Size type Physical size Formula symbol dimension SI unit Other units comment
el. amperage electric current ${\ displaystyle I}$ I. Ampere (A) Biot (bi)
el. current density electric current density ${\ displaystyle J, j, S}$ I · L −2 A m −2
el. charge electric charge ${\ displaystyle Q}$ IT Coulomb (C) A s
Franklin (Fr)
el. voltage electrical voltage , electrical potential difference ${\ displaystyle U}$ ML 2 T −3 I −1 Volt (V) W A −1
J C −1
el. potential electrical potential ${\ displaystyle \ varphi}$ ML 2 T −3 I −1 Volt (V) W A −1
J C −1
el. resistance ohmic resistance , effective resistance ${\ displaystyle R}$ ML 2 T −3 I −2 Ohm ( ) ${\ displaystyle \ Omega}$ V · A −1
el. resistance Reactance ${\ displaystyle X}$ ML 2 T −3 I −2 Ohm ( ) ${\ displaystyle \ Omega}$ V · A −1
el. resistance Impedance , impedance ${\ displaystyle Z}$ ML 2 T −3 I −2 Ohm ( ) ${\ displaystyle \ Omega}$ V · A −1
specific electrical resistance specific electrical resistance ${\ displaystyle \ varrho}$ ML 3 T −3 I −2 Ω m
el. conductance electrical conductance , effective conductance ${\ displaystyle G}$ M −1 L −2 T 3 I 2 Siemens (S) Ω −1 , A · V −1
el. conductance Susceptance ${\ displaystyle B}$ M −1 L −2 T 3 I 2 Siemens (S) Ω −1 , A · V −1
el. conductance Admittance , admittance ${\ displaystyle Y}$ M −1 L −2 T 3 I 2 Siemens (S) Ω −1 , A · V −1
specific electrical conductance specific electrical conductance ${\ displaystyle \ sigma}$ M −1 L −3 T 3 I 2 S m −1
force Lorentz force ${\ displaystyle F _ {\ mathrm {L}}}$ MLT −2 Newton (N) Dyn (dyn)
kilopond (kp)
el. field strength electric field strength ${\ displaystyle E}$ MLT −3 I −1 V m −1 N · C −1
el. river electric flow ${\ displaystyle \ Psi}$ IT C.
el. flux density electrical flux density (electrical excitation), displacement density ${\ displaystyle D}$ IL −2 T C m −2
el. polarization polarization ${\ displaystyle P}$ IL −2 T C m −2
el. polarizability Polarizability ${\ displaystyle \ alpha}$ M −1 I 2 T 4 C m 2 V −1
magnet. Flux density magnetic flux density , magnetic induction ${\ displaystyle B}$ MT −2 I −1 Tesla (T) Gauss (G)
γ
magnet. Flux density magnetic polarization ${\ displaystyle J \,}$ MT −2 I −1 Tesla (T) Gauss (G)
γ
magnet. Field strength magnetic field strength , magnetic excitation ${\ displaystyle H}$ L −1 I A m −1 Oersted (Oe)
magnetization magnetization ${\ displaystyle M}$ L −1 I A m −1
magnet. flow Magnetic river ${\ displaystyle {\ mathit {\ Phi}}}$ ML 2 T −2 I −1 Weber (Wb) Vs
Maxwell (M)
magnetic moment magnetic moment ${\ displaystyle \ mu}$ L 2 I A m 2
el. capacity electrical capacitance ${\ displaystyle C}$ M −1 L −2 T 4 I 2 Farad (F) C · V −1 , A · s · V −1
Elasticity Elasticity ${\ displaystyle S}$ ML 2 T −4 I −2 F −1
Inductance Inductance ${\ displaystyle L}$ ML 2 T −2 I −2 Henry (H) Wb · A −1
Permittivity Permittivity ${\ displaystyle \ epsilon}$ M −1 L −3 T 4 I 2 F m −1
permeability Magnetic permeability ${\ displaystyle \ mu}$ MLT −2 I −2 H m −1
power Apparent power ${\ displaystyle S}$ ML 2 T −3 Volt amperes (VA)
power Real power ${\ displaystyle P}$ ML 2 T −3 Watt (W)
power Reactive power ${\ displaystyle Q}$ ML 2 T −3 Var (var)
Charge density Line charge density ${\ displaystyle \ lambda}$ ITL −1 C m −1
Charge density Surface charge density ${\ displaystyle \ sigma}$ ITL −2 C m −2
Charge density Space charge density ${\ displaystyle \ rho}$ ITL −3 C m −3
magnet. potential magnetic potential ${\ displaystyle \ psi}$ I. A.
magnet. potential magnetic potential field ${\ displaystyle A}$ I. A.
magnet. tension magnetic flooding ${\ displaystyle \ Theta}$ I. A. AW, Aw
Gilbert (Gb)
magnet. flow magnetic interlinking flux ${\ displaystyle \ Psi}$ ML 2 T −2 I −1 Weber (Wb) V s
Maxwell (M)
Susceptibility electrical susceptibility ${\ displaystyle \ chi _ {e}}$ 1 1
Susceptibility magnetic susceptibility ${\ displaystyle \ chi, \ chi _ {\ mathrm {v}}, \ chi _ {\ mathrm {m}}, \ chi _ {\ mathrm {mag}}}$ 1 1
molar susceptibility molar susceptibility ${\ displaystyle \ chi _ {\ mathrm {mol}}}$ L 3 N −1 m 3 · mol -1
Mass susceptibility Mass susceptibility ${\ displaystyle \ chi _ {\ mathrm {mass}}, \ chi _ {\ mathrm {g}}, \ chi _ {\ mathrm {m}}}$ L 3 M −1 m 3 kg −1

## Atomic and Molecular

Size type Physical size Formula symbol dimension SI unit Other units comment
Amount of substance Amount of substance n N Mole (mol) Val (val)
molar volume molar volume ${\ displaystyle V _ {\ mathrm {m}} \,}$ L 3 N −1 m 3 mol −1
molar mass molar mass ${\ displaystyle M \,}$ MN −1 g mol −1
relative mass relative atomic mass ${\ displaystyle A _ {\ mathrm {r}} \,}$ 1 one
relative mass relative molecular weight ${\ displaystyle M _ {\ mathrm {r}} \,}$ 1 one
Value Charge number of an ion , valence of a substance B ${\ displaystyle z _ {\ mathrm {B}} \,}$ 1 one

## Nuclear physics

Size type Physical size Formula symbol dimension SI unit Other units comment
activity activity ${\ displaystyle A \,}$ T −1 Becquerel (Bq) Curie (unit) (Ci)
Stat (St)
Eman (eman)
Mache unit (ME)
specific activity specific activity ${\ displaystyle A \,}$ M −1 T −1 Bq kg −1
time Half-life ${\ displaystyle T _ {\ frac {1} {2}} \,}$ T Second (s)
time lifespan ${\ displaystyle \ tau \,}$ T Second (s)
reciprocal time Decay constant ${\ displaystyle \ lambda \,}$ T −1 s −1
specific energy Absorbed dose ${\ displaystyle D \,}$ L 2 T −2 Gray (Gy) J kg −1
Equivalent dose Equivalent dose ${\ displaystyle H \,}$ L 2 T −2 Sievert (Sv) J kg −1
Rem (rem)
Ion dose Ion dose ${\ displaystyle J \,}$ M −1 IT A s kg −1 X-ray (R)
surface Cross section ${\ displaystyle \ sigma \,}$ L 2 Square meter (m 2 ) Barn b

Size type Physical size Formula symbol dimension SI unit Other units comment
Power density Radiation intensity (radiation intensity) ${\ displaystyle I \,}$ ML 2 T −3 W sr −1 english radiant intensity
power Radiation flux ${\ displaystyle {\ mathit {\ Phi}} \,}$ ML 2 T −3 Watt (W) engl. radiant flux , radiant power
energy Radiant energy (amount of radiation) ${\ displaystyle Q \ ,, \, E}$ ML 2 T −2 Joule (J) engl. radiant energy
Radiance Radiance ${\ displaystyle L \,}$ MT −3 W m −2 sr −1 engl. radiance
Power density Irradiance ${\ displaystyle E \ ,, \, I}$ MT −3 W m −2 engl. irradiance
Power density specific charisma ${\ displaystyle M \,}$ MT −3 W m −2 engl. radiant exitance , radiant emittance
Energy density Irradiation ${\ displaystyle H \,}$ MT −2 J m −2 engl. radiant exposure

## Photometry and optics

Size type Physical size Formula symbol dimension SI unit Other units comment
Light intensity Light intensity ${\ displaystyle I _ {\ mathrm {v}} \,}$ J Candela  (cd) Hefner candle  (HK) english luminous intensity
Luminous flux Luminous flux ${\ displaystyle {\ mathit {\ Phi}} _ {\ mathrm {v}} \,}$, ,${\ displaystyle {\ mathit {F \,}}}$${\ displaystyle {\ mathit {P \,}}}$ J Lumen  (lm) cd sr engl. luminous flux , luminous power
Light output Light output ${\ displaystyle \ eta \,}$, ${\ displaystyle \ rho \,}$ M −1 L −2 T 3 J lm · W −1 , engl. luminous efficacy
Amount of light Amount of light ${\ displaystyle Q _ {\ mathrm {v}} \,}$ TJ Lumen second  (lm s) cd sr s engl. luminous energy
Luminance Luminance ${\ displaystyle L _ {\ mathrm {v}} \,}$ L −2 J cd · m -2 Stilb  (sb), Apostilb  (asb), Lambert  (la), Blondel , engl. luminance
Illuminance Illuminance ${\ displaystyle E _ {\ mathrm {v}} \,}$ L −2 J Lux  (lx) lm m −2 ,
Nox  (nx),
Phot  (ph)
, engl. illuminance
specific light emission specific light emission ${\ displaystyle M _ {\ mathrm {v}} \,}$ L −2 J lm m −2 engl. luminous emittance
exposure exposure ${\ displaystyle H _ {\ mathrm {v}} \,}$ L −2 TJ Lux second  (lx s) engl. luminous exposure
length Focal length ${\ displaystyle f \,}$ L. Meter (m) engl. focal length
reciprocal length Refractive index , refractive power ${\ displaystyle D \,}$ L −1 m −1 Diopter  (dpt) engl. diopter , dioptre

## Legend

1. ratio
2. related size
3. a b c process variable
4. energy quantity
5. field size
6. a b pseudo vector
7. Conservation size with regard to the homogeneity of the space
8. Conservation quantity with regard to the isotropy of space
9. Conservation size with regard to C-symmetry