Table of physical constants

Table of universal constants

Quantity	Symbol	Value	Relative Standard Uncertainty
characteristic impedance of vacuum	$Z_0 = \mu_0 c \,$	376.730 313 461... Ω	defined
electric constant (permittivity of free space)	$\epsilon_0 = 1 / ( \mu_0 c^2 )\,$	8.854 187 817... × 10^-12F·m^-1	defined
magnetic constant (permeability of free space)	$\mu_0 \,$	4π × 10^-7 N·A^-2 = 1.2566 370 614... × 10^-6 N·A^-2	defined
Newtonian constant of gravitation	$G \,$	6.6742(10) × 10^-11m³·kg^-1·s^-2	1.5 × 10^-4
Planck's constant	$h \,$	6.626 0693(11) × 10^-34 J·s	1.7 × 10^-7
Dirac's constant	$\hbar = h / (2 \pi)$	1.054 571 68(18) × 10^-34 J·s	1.7 × 10^-7
speed of light in vacuum	$c \,$	299 792 458 m·s^-1	defined

Table of electromagnetic constants

Quantity	Symbol	Value¹ (SI units)	Relative Standard Uncertainty
Bohr magneton	$\mu_B = e \hbar / 2 m_e$	927.400 949(80) × 10^-26 J·T^-1	8.6 × 10^-8
conductance quantum	$G_0 = 2 e^2 / h \,$	7.748 091 733(26) × 10^-5 S	3.3 × 10^-9
Coulomb's constant	$\kappa = 1 / 4\pi\epsilon_0 \,$	8.987 742 438 × 10⁹ N·m²C^-2	defined
elementary charge	$e \,$	1.602 176 53(14) × 10^-19 C	8.5 × 10^-8
Josephson constant	$K_J = 2 e / h \,$	483 597.879(41) × 10⁹ Hz· V^-1	8.5 × 10^-8
magnetic flux quantum	$\phi_0 = h / 2 e \,$	2.067 833 72(18) × 10^-15 Wb	8.5 × 10^-8
nuclear magneton	$\mu_N = e \hbar / 2 m_p$	5.050 783 43(43) × 10^-27 J·T^-1	8.6 × 10^-8
resistance quantum	$R_0 = h / 2 e^2 \,$	12 906.403 725(43) Ω	3.3 × 10^-9
von Klitzing constant	$R_K = h / e^2 \,$	25 812.807 449(86) Ω	3.3 × 10^-9

Table of atomic and nuclear constants

Quantity	Symbol	Value¹ (SI units)	Relative Standard Uncertainty
Bohr radius	$a_0 = \alpha / 4 \pi R_\infin \,$	0.529 177 2108(18) × 10^-10 m	3.3 × 10^-9
Fermi coupling constant	$G_F / (\hbar c)^3$	1.166 39(1) × 10^-5 GeV^-2	8.6 × 10^-6
fine-structure constant	$\alpha = \mu_0 e^2 c / (2 h) = e^2 / (4 \pi \epsilon_0 \hbar c) \,$	7.297 352 568(24) × 10^-3	3.3 × 10^-9
Hartree energy	$E_h = 2 R_\infin h c \,$	4.359 744 17(75) × 10^-18 J	1.7 × 10^-7
quantum of circulation	$h / 2 m_e \,$	3.636 947 550(24) × 10^-4 m² s^-1	6.7 × 10^-9
Rydberg constant	$R_\infin = \alpha^2 m_e c / 2 h \,$	10 973 731.568 525(73) m^-1	6.6 × 10^-12
Thomson cross section	$(8 \pi / 3)r_e^2$	0.665 245 873(13) × 10^-28 m²	2.0 × 10^-8
Weinberg angle\|weak mixing angle	$\sin^2 \theta_W = 1 - (m_W / m_Z)^2 \,$	0.222 15(76)	3.4 × 10^-3

Table of physico-chemical constants

Quantity		Symbol	Value¹ (SI units)	Relative Standard Uncertainty
atomic mass constant (unified atomic mass unit)		$m_u = 1 \ u \,$	1.660 538 86(28) × 10^-27 kg	1.7 × 10^-7
Avogadro's number		$N_A, L \,$	6.022 1415(10) × 10²³	1.7 × 10^-7
Boltzmann constant		$k = R / N_A \,$	1.380 6505(24) × 10^-23 J·K^-1	1.8 × 10^-6
Faraday constant		$F = N_A e \,$	96 485.3383(83)C·mol^-1	8.6 × 10^-8
first radiation constant		$c_1 = 2 \pi h c^2 \,$	3.741 771 38(64) × 10^-16 W·m²	1.7 × 10^-7
first radiation constant	for spectral radiance	$c_{1L} \,$	1.191 042 82(20) × 10^-16 W · m² sr^-1	1.7 × 10^-7
Loschmidt constant	at $T$ =273.15 K and $p$ =101.325 kPa	$n_0 = N_A / V_m \,$	2.686 7773(47) × 10²⁵ m^-3	1.8 × 10^-6
gas constant		$R \,$	8.314 472(15) J·K^-1·mol^-1	1.7 × 10^-6
molar Planck constant		$N_A h \,$	3.990 312 716(27) × 10^-10 J · s · mol^-1	6.7 × 10^-9
molar volume of an ideal gas	at $T$ =273.15 K and $p$ =100 kPa	$V_m = R T / p \,$	22.710 981(40) × 10^-3 m³ ·mol^-1	1.7 × 10^-6
molar volume of an ideal gas	at $T$ =273.15 K and $p$ =101.325 kPa	$V_m = R T / p \,$	22.413 996(39) × 10^-3 m³ ·mol^-1	1.7 × 10^-6
Sackur-Tetrode constant	at $T$ =1 K and $p$ =100 kPa	$S_0 / R = \frac{5}{2}$ $+ \ln\left[ (2\pi m_u k T / h^2)^{3/2} k T / p \right]$	-1.151 7047(44)	3.8 × 10^-6
Sackur-Tetrode constant	at $T$ =1 K and $p$ =101.325 kPa		-1.164 8677(44)	3.8 × 10^-6
second radiation constant		$c_2 = h c / k \,$	1.438 7752(25) × 10^-2 m·K	1.7 × 10^-6
Stefan-Boltzmann constant		$\sigma = (\pi^2 / 60) k^4 / \hbar^3 c^2$	5.670 400(40) × 10^-8 W·m^-2·K^-4	7.0 × 10^-6
Wien displacement law constant		$b = (h c / k) / \,$ 4.965 114 231...	2.897 7685(51) × 10^-3 m · K	1.7 × 10^-6

Table of adopted values

Quantity		Symbol	Value (SI units)	Relative Standard Uncertainty
conventional value of Josephson constant²		$K_{J-90} \,$	483 597.9 × 10⁹ Hz · V^-1	defined
conventional value of von Klitzing constant³		$R_{K-90} \,$	25 812.807 Ω	defined
molar mass	constant	$M_u = M(\,^{12}\mbox{C}) / 12$	1 × 10^-3 kg · mol^-1	defined
molar mass	of carbon-12	$M(\,^{12}\mbox{C}) = N_A m(\,^{12}\mbox{C})$	12 × 10^-3 kg · mol⁻¹	defined
standard acceleration of gravity (free fall on Earth)		$g_n \,\!$	9.806 65 m·s^-2	defined
standard atmosphere		$\mbox{atm} \,$	101 325 Pa	defined

Notes

¹The values are given in the so-called concise form; the number in brackets is the standard uncertainty, which is the value multiplied by the relative standard uncertainty.
²This is the value adopted internationally for realizing representations of the volt using the Josephson effect.
³This is the value adopted internationally for realizing representations of the ohm using the quantum Hall effect.