Table of Fundamental Physical Constants

This data is derived from the 1986 CODATA recommended values of the fundamental physical constants. It is not intended to be an authoritative source: typographical errors are possible and the data has been reformatted. You can find the more complete information from the NIST at http://physics.nist.gov/PhysRefData/codata86/codata86.html.
# Constant Symbol Value Units 
1 Speed of light in vacuum  (c)  299792458 m s-1 
2 Permeability of vacuum  (mu_0)  1.25663706143592e-06 N A-2 
3 Permittivity of vacuum  (epsilon_0)  8.854187817e-12 F m-1 
4 Newtonian constant of gravitation  (G)  6.67259e-11 ± 8.5e-15 m3 kg-1 s-2 
5 Planck constant  (h)  6.6260755e-34 ± 4.0e-40 J s 
6 Planck constant in eV    4.1356692e-15 ± 1.2e-21 eV s 
7 h-bar  (h-bar)  1.05457266e-34 ± 6.3e-41 J s 
8 h-bar in eV    6.582122e-16 ± 2.0e-22 eV s 
9 Planck mass  (m_p)  2.17671e-08 ± 1.4e-12 kg 
10 Planck length  (l_p)  1.61605e-35 ± 1.0e-39
11 Planck time  (t_p)  5.39056e-44 ± 3.4e-48
12 Elementary charge  (e)  1.60217733e-19 ± 4.9e-26
13 Magnetic flux quantum  (Phi_0)  2.06783461e-15 ± 6.1e-22 Wb 
14 Josephson frequency-voltage quotient    483597670000000 ± 1.4e+08 V-1 s-1 
15 Quantized Hall conductance    3.87404614e-05 ± 1.7e-12 Omega-1 
16 Quantized Hall resistance  (R_H)  25812.8056 ± 0.0012 Omega 
17 Bohr magneton  (mu_B)  9.2740154e-24 ± 3.1e-30 J T-1 
18 Bohr magneton in eV    5.78838263e-05 ± 5.2e-12 eV T-1 
19 Bohr magneton in Hz    13996241800 ± 4200 T-1 s-1 
20 Bohr magneton in wavenumbers    46.686437 ± 1.4e-05 m-1 T-1 
21 Bohr magneton in kelvins    0.6717099 ± 5.7e-06 K T-1 
22 Nuclear magneton  (mu_N)  5.0507866e-27 ± 1.7e-33 J T-1 
23 Nuclear magneton in eV    3.15245166e-08 ± 2.8e-15 eV T-1 
24 Nuclear magneton in Hz    7622591.4 ± 2.3 T-1 s-1 
25 Nuclear magneton in wavenumbers    0.0254262281 ± 7.7e-09 m-1 T-1 
26 Nuclear magneton in kelvins    0.0003658246 ± 3.1e-09 K T-1 
27 Fine structure constant  (alpha)  0.00729735308 ± 3.3e-10  
28 Inverse fine structure constant    137.0359895 ± 6.1e-06  
29 Rydberg constant  (Ry)  10973731.534 ± 0.013 m-1 
30 Rydberg constant in Hz    3.2898419499e+15 ± 3.9e+06 s-1 
31 Rydberg constant in joules    2.1798741e-18 ± 1.3e-24
32 Rydberg constant in eV    13.6056981 ± 4.0e-06 eV 
33 Bohr radius  (a_0)  5.29177249e-11 ± 2.4e-18
34 Hartree energy  (E_h)  4.3597482e-18 ± 2.6e-24
35 Hartree energy in eV    27.2113961 ± 8.1e-06 eV 
36 Quantum of circulation    0.000363694807 ± 3.3e-11 m2 s-1 
37 Electron mass  (m_e)  9.1093897e-31 ± 5.4e-37 kg 
38 Electron mass in u    0.000548579903 ± 1.3e-11
39 Electron mass in eV    510999.06 ± 0.15 eV 
40 Electron-muon mass ratio    0.00483633218 ± 7.1e-10  
41 Electron-proton mass ratio    0.000544617013 ± 1.1e-11  
42 Electron-deuteron mass ratio    0.000272443707 ± 6e-12  
43 Electron-alpha-particle mass ratio    0.000137093354 ± 3e-12  
44 Electron specific charge    -175881962000 ± -53000 C kg-1 
45 Electron molar mass    5.48579903e-07 ± 1.3e-14 kg mol-1 
46 Electron Compton wavelength  (lambda_C)  2.42631058e-12 ± 2.2e-19
47 Electron Compton wavelength over 2 pi  (lambda-bar_C) 3.86159323e-13 ± 3.5e-20
48 Electron classical radius  (r_e)  2.81794092e-15 ± 3.8e-22
49 Electron Thomson cross section  (sigma_e)  6.6524616e-29 ± 1.8e-35 m2 
50 Electron magnetic moment    9.2847701e-24 ± 3.1e-30 J T-1 
51 Electron magnetic moment in Bohr magnetons   1.001159652193 ± 1.0e-11  
52 Electron magnetic moment in nuclear magnetons   1838.282 ± 3.7e-05  
53 Electron magnetic moment anomaly  (a_e)  0.001159652193 ± 1.0e-11  
54 Electron g-factor  (g_e)  2.002319304386 ± 2.0e-11  
55 Electron-muon magnetic moment ratio    206.766967 ± 3.0e-05  
56 Electron-proton magnetic moment ratio    658.2106881 ± 6.6e-06  
57 Muon mass    1.8835327e-28 ± 1.1e-34 kg 
58 Muon mass in u    0.113428913 ± 1.7e-08
59 Muon mass in eV    105658389 ± 34 eV 
60 Muon-electron mass ratio    206.768262 ± 3.0e-05  
61 Muon molar mass    0.000113428913 ± 1.7e-11 kg mol-1 
62 Muon magnetic moment    4.4904514e-26 ± 1.5e-32 J T-1 
63 Muon magnetic moment in Bohr magnetons    0.00484197097 ± 7.1e-10  
64 Muon magnetic moment in nuclear magnetons   8.8905981 ± 1.3e-06  
65 Muon magnetic moment anomaly  (a_mu)  0.001165923 ± 8.4e-09  
66 Muon g-factor  (g_mu)  2.002331846 ± 1.7e-08  
67 Muon-proton magnetic moment ratio    3.18334547 ± 4.7e-07  
68 Proton mass  (m_p)  1.6726231e-27 ± 1.0e-33 kg 
69 Proton mass in u    1.00727647 ± 1.2e-08
70 Proton mass in eV    938272310 ± 280 eV 
71 Proton-electron mass ratio    1836.152701 ± 3.7e-05  
72 Proton-muon mass ratio    8.8802444 ± 1.3e-06  
73 Proton specific charge    95788309 ± 29 C kg-1 
74 Proton molar mass    0.00100727647 ± 1.2e-11 kg mol-1 
75 Proton Compton wavelength  (lambda_C,p) 1.32141002e-15 ± 1.2e-22
76 Proton magnetic moment    1.41060761e-26 ± 4.7e-33 J T-1 
77 Proton magnetic moment in Bohr magnetons   0.001521032202 ± 1.5e-11  
78 Proton magnetic moment in nuclear magnetons   2.792847386 ± 6.3e-08  
79 Diamagnetic shielding correction for protons (H_2 O, spherical sample, 298.15 K) (sigma_H2O)  2.5689e-05 ± 1.5e-08  
80 Shielded proton moment (H_2 O, spherical sample, 298.15 K) (mu_p')  1.41057138e-26 ± 4.7e-33 J T-1 
81 Shielded proton moment in Bohr magnetons   0.001520993129 ± 1.7e-11  
82 Shielded proton moment in nuclear magnetons   2.792775642 ± 6.4e-08  
83 Proton gyromagnetic ratio  (gamma_p)  267522128 ± 81 T-1 s-1 
84 (gamma_p)  42577469 ± 13 T-1 s-1 
85 Proton gyromagnetic ratio, uncorrected (H_2 O, spherical sample, 298.15 K) (gamma_p')  267515255 ± 81 T-1 s-1 
86 (gamma_p'/2pi) 42576375 ± 13 T-1 s-1 
87 Neutron mass  (m_n)  1.6749286e-27 ± 1.0e-33 kg 
88 Neutron mass in u    1.008664904 ± 1.4e-08
89 Neutron mass in eV    939565630 ± 280 eV 
90 Neutron-electron mass ratio    1838.683662 ± 4.0e-05  
91 Neutron-proton mass ratio    1.001378404 ± 9e-09  
92 Neutron molar mass    0.001008664904 ± 1.4e-11 kg mol-1 
93 Neutron Compton wavelength  (lambda_C,n) 1.3195911e-15 ± 1.2e-22
94 Neutron magnetic moment    9.6623707e-27 ± 4.0e-33 J T-1 
95 Neutron magnetic moment in Bohr magnetons   0.00104187563 ± 2.5e-10  
96 Neutron magnetic moment in nuclear magnetons   1.91304275 ± 4.5e-07  
97 Neutron-electron magnetic moment ratio    0.00104066882 ± 2.5e-10  
98 Neutron-proton magnetic moment ratio    0.68497934 ± 1.6e-07  
99 Deuteron mass  (m_d)  3.343586e-27 ± 2.0e-33 kg 
100 Deuteron mass in u    2.013553214 ± 2.4e-08
101 Deuteron mass in eV    1875613390 ± 570 eV 
102 Deuteron-electron mass ratio    3670.483014 ± 7.5e-05  
103 Deuteron-proton mass ratio    1.999007496 ± 6e-09  
104 Deuteron molar mass    0.002013553214 ± 2.4e-11 kg mol-1 
105 Deuteron magnetic moment  (mu_d)  4.3307375e-27 ± 1.5e-33 J T-1 
106 Deuteron magnetic moment in Bohr magnetons   0.0004669754479 ± 9.1e-12  
107 Deuteron magnetic moment in nuclear magnetons   0.85743823 ± 2.4e-08  
108 Deuteron-electron magnetic moment ratio    0.000466434546 ± 9.1e-12  
109 Deuteron-proton magnetic moment ratio    0.3070122035 ± 5.1e-09  
110 Avagadro constant  (N_A)  6.0221367e+23 ± 3.6e+17 mol-1 
111 Atomic mass constant  (m_u)  1.6605402e-27 ± 1.0e-33 kg 
112 Atomic mass constant in eV    931494320 ± 280 eV 
113 Faraday constant  (F)  96485.309 ± 0.029 C mol-1 
114 Molar Planck constant    3.99031323e-10 ± 3.6e-17 J s mol-1 
115 (N_A hc)  0.11962658 ± 1.1e-07 J m mol-1 
116 Molar gas constant  (R)  8.31451 ± 7.0e-05 J mol-1 K-1 
117 Boltzmann constant  (k)  1.380658e-23 ± 1.2e-28 J K-1 
118 Boltzmann constant in eV    8.617385e-05 ± 7.3e-10 eV K-1 
119 Boltzmann constant in Hz    20836740000 ± 180000 K-1 s-1 
120 Boltzmann constant in wavenumbers    69.50387 ± 0.00059 m-1 K-1 
121 Molar volume (ideal gas), STP  (V_m)  0.0224141 ± 1.9e-07 m3 mol-1 
122 Loschmidt constant  (n_0)  2.686763e+25 ± 2.3e+20 m-3 
123 Stefan-Boltzmann constant  (sigma)  5.67051e-08 ± 1.9e-12 W m-2 K-4 
124 First radiation constant  (c_1)  3.7417749e-16 ± 2.2e-22 W m2 
125 Second radiation constant  (c_2)  0.01438769 ± 1.2e-07 m K 
126 Wien displacement law constant  (b)  0.002897756 ± 2.4e-08 m K 
127 Electron volt  (eV)  1.60217733e-19 ± 4.9e-26
128 Atomic mass unit  (u)  1.6605402e-27 ± 1.0e-33 kg 
129 Standard atmosphere  (atm)  101325 Pa 
130 Standard acceleration of gravity  (g_n)  9.80665 m s-2 
131 BIPM-maintained ohm, Omega_69-B1 as of 1 Jan 85 (Omega_B185) 1-1.563e-6 ± 5.0e-08 Omega 
132 Drift rate of Omega_69-B1  (dOmega_69-B1/dt) -0.0566 ± -0.0015 muOmega/yr 
133 BIPM-maintained volt 483 694 GHz(h/2e)  (V_76-B1)  1-7.59e-6 ± 3.0e-07
134 BIPM maintained ampere A_BIPM  (A_B185)  1-6.03e-6 ± 3.0e-07
135 Cu x-unit:  (xu(CuKalpha1)) 1.00207789e-13 ± 7.0e-20
136 Mo x-unit:  (xu(MoKalpha1)) 1.00209938e-13 ± 4.5e-20
137 AA *:  (AAngstrom-star) 1.00001481e-10 ± 9.2e-17
138 Lattice spacing of Si (in vacuum, 295.65 K) (a)  5.4310196e-10 ± 1.1e-16
139 Lattice spacing Si (220) plane  (d_220)  1.9201554e-10 ± 4.0e-17
140 Molar volume of Si  (V_m(Si))  1.20588179e-05 ± 8.9e-12 m3 mol-1 

Table Version 1.1