# 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) | $\varepsilon _{0}=1/(\mu _{0}c^{2})\,$ | 8.854 187 817... × 10$^{-12}$F·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 |
| gravitational constant (Newtonian constant of gravitation) | $G\,$ | 6.6742(10) × 10$^{-11}$m$^3$·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 | Value$^1$ (SI units) | Relative Standard Uncertainty |
| Bohr magneton | $\mu _{B}=e\hbar /2m_{e}$ | 927.400 949(80) × 10$^{-26}$ J·T$^{-1}$ | 8.6 × 10$^{-8}$ |
| conductance quantum | $G_{0}=2e^{2}/h\,$ | 7.748 091 733(26) × 10$^{-5}$ S | 3.3 × 10$^{-9}$ |
| Coulomb's constant | $\kappa =1/4\pi \varepsilon _{0}\,$ | 8.987 742 438 × 10$^9$ N·m$^2$C$^{-2}$ | defined |
| elementary charge | $e\,$ | 1.602 176 53(14) × 10$^{-19}$ C | 8.5 × 10$^{-8}$ |
| Josephson constant | $K_{J}=2e/h\,$ | 483 597.879(41) × 10$^9$ Hz· V$^{-1}$ | 8.5 × 10$^{-8}$ |
| magnetic flux quantum | $\phi _{0}=h/2e\,$ | 2.067 833 72(18) × 10$^{-15}$ Wb | 8.5 × 10$^{-8}$ |
| nuclear magneton | $\mu _{N}=e\hbar /2m_{p}$ | 5.050 783 43(43) × 10$^{-27}$ J·T$^{-1}$ | 8.6 × 10$^{-8}$ |
| resistance quantum | $R_{0}=h/2e^{2}\,$ | 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 | Quantity | Symbol | Value$^1$ (SI units) | Relative Standard Uncertainty |
| Bohr radius | Bohr radius | $a_{0}=\alpha /4\pi R_{\infty }\,$ | 0.529 177 2108(18) × 10$^{-10}$ m | 3.3 × 10$^{-9}$ |
| Fermi coupling constant | Fermi coupling constant | $G_{F}/(\hbar c)^{3}$ | 1.166 39(1) × 10$^{-5}$ GeV$^{-2}$ | 8.6 × 10$^{-6}$ |
| fine structure constant | fine structure constant | $\alpha =\mu _{0}e^{2}c/(2h)=e^{2}/(4\pi \varepsilon _{0}\hbar c)\,$ | 7.297 352 568(24) × 10$^{-3}$ | 3.3 × 10$^{-9}$ |
| Hartree energy | Hartree energy | $E_{h}=2R_{\infty }hc\,$ | 4.359 744 17(75) × 10$^{-18}$ J | 1.7 × 10$^{-7}$ |
| quantum of circulation | quantum of circulation | $h/2m_{e}\,$ | 3.636 947 550(24) × 10$^{-4}$ m$^2$ s$^{-1}$ | 6.7 × 10$^{-9}$ |
| Rydberg constant | Rydberg constant | $R_{\infty }=\alpha ^{2}m_{e}c/2h\,$ | 10 973 731.568 525(73) m$^{-1}$ | 6.6 × 10$^{-12}$ |
| Thomson cross section | Thomson cross section | $(8\pi /3)r_{e}^{2}$ | 0.665 245 873(13) × 10$^{-28}$ m$^2$ | 2.0 × 10$^{-8}$ |
| Weinberg angle|weak mixing angle | 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 | Quantity | Symbol | Value$^1$ (SI units) | Relative Standard Uncertainty |
| atomic mass constant (unified atomic mass unit) | 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 | Avogadro's number | $N_{A},L\,$ | 6.0221417(10) × 10$^{23}$ | 1.7 × 10$^{-7}$ |
| Boltzmann constant | Boltzmann constant | $k=R/N_{A}\,$ | 1.380 6505(24) × 10$^{-23}$ J·K$^{-1}$ | 1.8 × 10$^{-6}$ |
| Faraday constant | Faraday constant | $F=N_{A}e\,$ | 96 485.3383(83)C·mol$^{-1}$ | 8.6 × 10$^{-8}$ |
| first radiation constant | | $c_{1}=2\pi hc^{2}\,$ | 3.741 771 38(64) × 10$^{-16}$ W·m$^2$ | 1.7 × 10$^{-7}$ |
| first radiation constant | for spectral radiance | $c_{1L}\,$ | 1.191 042 82(20) × 10$^{-16}$ W · m$^2$ 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) × 10$^{25}$ m$^{-3}$ | 1.8 × 10$^{-6}$ |
| gas constant | gas constant | $R\,$ | 8.314 472(15) J·K$^{-1}$·mol$^{-1}$ | 1.7 × 10$^{-6}$ |
| molar Planck constant | 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 | $V_{m}=RT/p\,$ | 22.710 981(40) × 10$^{-3}$ m$^3$ ·mol$^{-1}$ | 1.7 × 10$^{-6}$ |
| molar volume of an ideal gas | at $T$=273.15 K and $p$=101.325 kPa | $V_{m}=RT/p\,$ | 22.413 996(39) × 10$^{-3}$ m$^3$ ·mol$^{-1}$ | 1.7 × 10$^{-6}$ |
| Sackur-Tetrode constant | at $T$=1 K and $p$=100 kPa | $S_{0}/R={\frac {5}{2}}$ $+\ln \left[(2\pi m_{u}kT/h^{2})^{3/2}kT/p\right]$ | -1.151 7047(44) | 3.8 × 10$^{-6}$ |
| Sackur-Tetrode constant | at $T$=1 K and $p$=101.325 kPa | $S_{0}/R={\frac {5}{2}}$ $+\ln \left[(2\pi m_{u}kT/h^{2})^{3/2}kT/p\right]$ | -1.164 8677(44) | 3.8 × 10$^{-6}$ |
| second radiation constant | second radiation constant | $c_{2}=hc/k\,$ | 1.438 7752(25) × 10$^{-2}$ m·K | 1.7 × 10$^{-6}$ |
| Stefan-Boltzmann constant | 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 | Wien displacement law constant | $b=(hc/k)/\,$ 4.965 114 231... | 2.897 7685(51) × 10$^{-3}$ m · K | 1.7 × 10$^{-6}$ |

## Table of adopted values

| Quantity | Quantity | Symbol | Value (SI units) | Relative Standard Uncertainty |
| conventional value of Josephson constant$^2$ | conventional value of Josephson constant$^2$ | $K_{J-90}\,$ | 483 597.9 × 10$^9$ Hz · V$^{-1}$ | defined |
| conventional value of von Klitzing constant$^3$ | conventional value of von Klitzing constant$^3$ | $R_{K-90}\,$ | 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) | standard acceleration of gravity (free fall on Earth) | $g_{n}\,\!$ | 9.806 65 m·s$^{-2}$ | defined |
| standard atmosphere | standard atmosphere | ${\mbox{atm}}\,$ | 101 325 Pa | defined |