List of physical quantities

This article consists of tables outlining a number of physical quantities. A physical quantity is a property of a material or system that can be quantified by measurement; it has a value and units. The International System of Quantities, which underlies the International System of Units, defines seven base quantities; other quantities are generally derived quantities, which can be expressed in terms of the base quantities.
Neither the names nor the symbols used for the physical quantities are set by international standards, although ISO/IEC 80000 does list many of these without making them normative. Some quantities are known by several different names and symbols. The table typically lists the name and symbol that is most commonly used.
The final column lists some properties and characteristics that a quantity has, such as their scaling behaviour, their transformation properties, and whether the quantity is conserved.

Scalar

Name	Symbol	Description	SI unit	Quantity dimension	Comments
absorbed dose rate	D	Absorbed dose received per unit of time	Gy/s	L² T⁻³
action	S	Momentum of particle multiplied by distance travelled	J/Hz	M 'L² T'⁻¹
amount of substance	n	The quantity proportional to the number of particles in a sample, with the Avogadro constant as the proportionality constant	mole	N	ISQ base quantity, extensive
angle	θ	Angular distance	radian	1
angular acceleration	ω_a	Change in angular velocity per unit time	rad/s²	T⁻²
area	A, S	Extent of a two-dimensional geometric shape	m²	L²	extensive, bivector or scalar
area density	ρ_A	Mass per unit area	kg⋅m⁻²	M 'L⁻²	intensive
capacitance	C''	Stored charge per unit electric potential	farad	M'⁻¹ L⁻² T⁴ I²
catalytic activity concentration		Change in reaction rate due to presence of a catalyst per unit volume of the system	kat⋅m⁻³	L⁻³ T⁻¹ N	intensive
chemical potential	μ''	Energy per unit change in amount of substance	J/mol	M 'L² T'⁻² N⁻¹	intensive
density	ρ	Mass per unit volume	kg/m³	M 'L⁻³	intensive
dose equivalent	H''	Received radiation adjusted for the effect on biological tissue	sievert	L'² T⁻²	intensive
electric charge	Q''	The force per unit electric field strength	coulomb	T 'I	extensive, conserved
electric charge density	ρ_Q	Electric charge per unit volume	C/m³	L'⁻³ T 'I	intensive
electrical conductance	G''	Measure for how easily current flows through a material	siemens	M'⁻¹ L⁻² T³ I²
electrical conductivity	σ''	Measure of a material's ability to conduct an electric current	S/m	M⁻¹ L⁻³ T³ I²
electric current	I	Rate of flow of electrical charge per unit time	ampere	I	ISQ base quantity, extensive
electric potential	φ	Energy required to move a unit charge through an electric field from a reference point	volt	M 'L² T'⁻³ I⁻¹	extensive
electrical resistance	R	Electric potential per unit electric current	ohm	M 'L² T'⁻³ I⁻²	extensive, assumes linearity
electrical resistivity	ρ_e	Bulk property equivalent of electrical resistance	ohm-metre	M 'L³ T'⁻³ I⁻²	extensive, conserved
energy	E	Energy	joule	M 'L² T'⁻²
energy density	U	Energy per volume	J⋅m⁻³	M 'L⁻¹ T'⁻²	intensive
entropy	S	Logarithmic measure of the number of available states of a system	J/K	M 'L² T'⁻² Θ⁻¹	extensive
frequency	f	Number of occurrences per unit time	hertz	T⁻¹
half-life	t_1/2	Time for a quantity to decay to half its initial value	s	T
heat	Q	Heat	joule	M 'L² T'⁻²
heat capacity	C_p	Energy per unit temperature change	J/K	M 'L² T'⁻² Θ⁻¹	extensive
heat flux density	ϕ_Q	Heat flow per unit time per unit surface area	W/m²	M 'T⁻³
illuminance	E''_v	Wavelength-weighted luminous flux per unit surface area	lux	L'⁻² J	intensive
impedance	Z''	Resistance to an alternating current of a given frequency, including effect on phase	ohm	M 'L² T'⁻³ I⁻²	complex scalar
inductance	L	Magnetic flux generated per unit current through a circuit	henry	M 'L² T'⁻² I⁻²
irradiance	E	Electromagnetic radiation power per unit surface area	W/m²	M 'T⁻³	intensive
intensity	I''	Power per unit cross sectional area	W/m²	M' T⁻³	intensive
kinetic energy	KE	The work or force in the direction of motion times displacement	joule	M 'L² T'⁻²	extensive
length	l'', L	linear extent between two points, which may be along some path	metre	L	ISQ base quantity, extensive
linear density	ρ_l	Mass per unit length	kg⋅m⁻¹	M 'L⁻¹
luminous intensity	I''_v	Wavelength-weighted power of emitted light per unit solid angle	candela	J'	ISQ base quantity
luminous flux	F''	Perceived power of a light source	lumen	J	extensive
Mach number	M	Ratio of flow velocity to the local speed of sound	1	1	intensive
magnetic flux	Φ	Measure of magnetism, taking account of the strength and the extent of a magnetic field	weber	M 'L² T'⁻² I⁻¹
mass	m	A measure of resistance to acceleration	kilogram	M	ISQ base quantity, extensive
mass fraction	x	Mass of a substance as a fraction of the total mass	1	1	intensive
mean lifetime	τ	Average time for a particle of a substance to decay	s	T	intensive
molar concentration	C	Amount of substance per unit volume	mol⋅m⁻³	L⁻³ N	intensive
molar energy		Amount of energy present in a system per unit amount of substance	J/mol	M 'L² T'⁻² N⁻¹	intensive
molar entropy	S°	Entropy per unit amount of substance	J/	M 'L² T'⁻² Θ⁻¹ N⁻¹	intensive
molar heat capacity	c	Heat capacity of a material per unit amount of substance	J/	M 'L² T'⁻² Θ⁻¹ N⁻¹	intensive
moment of inertia	I	Inertia of an object with respect to angular acceleration	kg⋅m²	M 'L²	extensive, tensor, scalar
optical power	P''	Measure of the effective curvature of a lens or curved mirror; inverse of focal length	dioptre	L'⁻¹	intensive
permeability	μ_s	Measure for how the magnetization of material is affected by the application of an external magnetic field	H/m	M 'L T'⁻² I⁻²	intensive
permittivity	ε_s	Measure for how the polarization of a material is affected by the application of an external electric field	F/m	M⁻¹ L⁻³ T⁴ I²	intensive
plane angle	θ''	Ratio of circular arc length to radius	radian	1	intensive
potential energy	PE	The energy of an object or system due to the body's position relative to other objects, or the configuration of its particles	joule	M 'L² T'⁻²
power	P	Rate of transfer of energy per unit time	watt	M 'L² T'⁻³	extensive
pressure	p	Force per unit area	pascal	M 'L⁻¹ T'⁻²	intensive
activity	A	Number of particles decaying per unit time	becquerel	T⁻¹	extensive
dose	D	Ionizing radiation energy absorbed per unit mass	gray	L² T⁻²
radiance	L	Power of emitted electromagnetic radiation per unit solid angle per emitting source area	W/	M 'T⁻³
radiant intensity	I''	Power of emitted electromagnetic radiation per unit solid angle	W/sr	M' L² T⁻³
reaction rate	r''	Rate of a chemical reaction for unit time	mol/	L⁻³ T⁻¹ N	intensive
refractive index	n	Factor by which the phase velocity of light is reduced in a medium	1	1	intensive
reluctance		Resistance to the flow of magnetic flux	H⁻¹	M⁻¹ L⁻² T² I²
solid angle	Ω	Ratio of area on a sphere to its radius squared	steradian	1	intensive
specific energy	e	Energy density per unit mass	J⋅kg⁻¹	L² T⁻²	intensive
specific heat capacity	c	Heat capacity per unit mass	J/	L² T⁻² Θ⁻¹	intensive
specific volume	v	Volume per unit mass	m³⋅kg⁻¹	M⁻¹ L³	intensive
speed	v	magnitude of velocity	m/s	L 'T⁻¹	intensive
spin	S''	Quantum-mechanically defined angular momentum of a particle	kg⋅m²⋅s⁻¹	M' L² T⁻¹
strain	ε''	Extension per unit length	1	1	intensive
stress	σ	Force per unit oriented surface area	Pa	M 'L⁻¹ T'⁻²	order 2 tensor
surface tension	γ	Energy change per unit change in surface area	N/m or J/m²	M 'T⁻²
temperature	T''	Average kinetic energy per degree of freedom of a system	kelvin	Θ'	ISQ base quantity, intensive
time	t''	The duration of an event	second	T	ISQ base quantity, extensive
thermal conductance	κ, λ	Measure for the ease with which an object conducts heat	W/K	M 'L² T'⁻³ Θ⁻¹	extensive
thermal conductivity	λ	Measure for the ease with which a material conducts heat	W/	M 'L T'⁻³ Θ⁻¹	intensive
Thermal resistance	R	Measure for the ease with which an object resists conduction of heat	K/W	M⁻¹ L⁻² T³ Θ	extensive
Thermal resistivity	R_λ	Measure for the ease with which a material resists conduction of heat	K⋅m/W	M⁻¹ L⁻¹ T³ Θ	intensive
viscosity	η	The measure of the internal friction in a fluid	Pa⋅s	M 'L⁻¹ T'⁻¹	intensive
volume	V	Three dimensional extent of an object	m³	L³	extensive
volumetric flow rate	Q	Rate of change of volume with respect to time	m³⋅s⁻¹	L³ T⁻¹	extensive
wavelength	λ	length of the repetition interval of a wave as measured in the direction of propagation	m	L
wavenumber	k	Repetency or spatial frequency: the inverse of the wavelength	m⁻¹	L⁻¹	intensive
work	W	Transferred energy	joule	M 'L² T'⁻²
Young's modulus	E	Ratio of stress to strain	pascal	M 'L⁻¹ T'⁻²	scalar; assumes isotropic linear material
spring constant	k	k is the torsional constant, which characterizes the stiffness of the torsional spring or the resistance to angular displacement.	N/m	M 'T'⁻²