Physics Constant Table
Constant Name
Symbol
Value
Dimension
Definition (Notes)
acceleration due to gravity
g
9.80665
m/s2
atomic mass unit, unified
u
1.660538782(83) × 10-27
kg
(Mass of 12C)/12
astronomical unit
au
1.4959787066(30) × 1011
m
Mean Earth to Sun distance
R
6.02214179(30) × 1023
mol-1
Particles in a mole of substance
Bohr magneton
µB
9.27400915(23) × 10-24
m2•A
aoo
5.2917720859(36) × 10-11
m
= α/(4πR)
Boltzmann constant
k
1.3806504(24) × 10-23
J/K
Charge/Quantum ratio

2.417989454(60) × 1014
A/J
= e/h
Conductance quantum
G0
7.7480917004(53) × 10-5
S
= 2e2/h
day, mean sidereal
dsidereal
86164.090530833
s
23h + 56m +4.090 530833s
deuteron (2H) mass
md
3.34358320(17) × 10-27
Kg
1875.612793(47) MeV/c2 = 2.013553212724(78) u
Earth mass
ME
5.9736(76) × 1024
Kg
RE
6.37814 × 106
m
electron charge magnitude
eV
1.602176487(40) × 10-19
C
electron rest mass
me
9.10938215(45) × 10-31
Kg
0.510998910(13) MeV = 5.4857990942(23) × 10-4 u
re
2.8179402894(58) × 10-15
m
= e2(4πε0mec2)
electron Compton wavelength
λe
2.4263102175(33) × 10-12
m
= h/cme
fine structure constant
α
7.2973525376(50) × 10-3
N/A
= μ0ce2/2h
gravitation constant
G
6.67428(67) × 10-11
m3/(kg.s2)
= GM1M2/r122
Hubble constant
H0
2.29(13) × 10-18
s-1
Josephson constant
KJ
4.83597891(12) × 10-14
Hz/V
= 2e/h
light year (deprecated)
ly
9.4607304 × 1016
m
magnetic constant (vacuum permeability)
µ0
2.067833667(52) × 10-15
W.b
= h/2e
magnetic flux quantum
Φ0
1.2566370614 × 10-6
N·A-2
= 4π × 10-7 N·A-2
Naperian (natural) logarithm base
e
2.718281828459045235

nuclear magneton
µN
5.05078324(13) × 10-27
Kg
parsec (au/arcsec)
pc
3.08568025 × 1016
m
permittivity of free space
ε0
8.854187817 × 10-12
F/m
Planck constant
h
6.62606896(33) × 10-34
J.s
Planck constant, reduced (Angular)
hbar
1.054 571628(53) × 10-34
J.s
Planck length
lp
1.616252(81) × 10-35
m
= ctp
Planck mass
mp
2.17644(11) × 10-8
kg
= √(h/2π)c/G
Planck time
tp
5.39124(27) × 10-44
s
= (h/2π)/mpc2
Planck temperature

1.416785(71) × 1032
K
= mpc2/k
proton rest mass
mp
1.672621637(83) × 10-27
kg
Quantum of circulation

3.6369475199(50) × 10-4
m2/s
= h/2me
Rydberg energy
R
1.0973731568527(73) × 107
m-1
= cα2me/2h
speed of light in vacuum
c
2.99792458 × 108
m/s
Stefan-Boltzmann constant
σ
5.6704(40) × 10-8
W/(m2 K4)
= 2π5k4/15h3c2
Thompson cross section
σT
6.6524 × 10-29
m2
= 8π.r02/3
Wien displacement law constant
b
2.8977685(51) × 10-3
m.K
year, sidereal (fixed star to fixed star, 1994)
ysidereal
31558149.8
s
year, tropical (equinox to equinox, 1994)
y
31556925.2
s
Von Klitzing constant
RK
2.5812807557(18) × 104
Ω
= h/e2