The following table lists the 1986 CODATA recommended values of the fundamental physical constants. The current values, "1998 CODATA recommended values", became available in July 1999, with details to be published in early 2000. You can find the latest data 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) | 6.6725985e-11 ± 8.54093e-15 | m3 kg-1 s-2 |
| 5 | Planck constant | (h) | 6.62607554e-34 ± 3.97565e-40 | J s |
| 6 | Planck constant in eV | 4.135669212e-15 ± 1.2407e-21 | eV s | |
| 7 | h-bar | (h-bar) | 1.0545726663e-34 ± 6.32744e-41 | J s |
| 8 | h-bar in eV | 6.58212202e-16 ± 1.97464e-22 | eV s | |
| 9 | Planck mass | (m_p) | 2.1767114e-08 ± 1.3931e-12 | kg |
| 10 | Planck length | (l_p) | 1.616051e-35 ± 1.03427e-39 | m |
| 11 | Planck time | (t_p) | 5.3905634e-44 ± 3.44996e-48 | s |
| 12 | Elementary charge | (e) | 1.6021773349e-19 ± 4.80653e-26 | C |
| 13 | Magnetic flux quantum | (Phi_0) | 2.0678346161e-15 ± 6.2035e-22 | Wb |
| 14 | Josephson frequency-voltage quotient | 483597671400000 ± 1.45079e+08 | V-1 s-1 | |
| 15 | Quantized Hall conductance | 3.8740461417e-05 ± 1.74332e-12 | Omega-1 | |
| 16 | Quantized Hall resistance | (R_H) | 25812.805612 ± 0.00116158 | Omega |
| 17 | Bohr magneton | (mu_B) | 9.274015431e-24 ± 3.15317e-30 | J T-1 |
| 18 | Bohr magneton in eV | 5.7883826352e-05 ± 5.15166e-12 | eV T-1 | |
| 19 | Bohr magneton in Hz | 13996241842 ± 4198.87 | T-1 s-1 | |
| 20 | Bohr magneton in wavenumbers | 46.68643714 ± 1.40059e-05 | m-1 T-1 | |
| 21 | Bohr magneton in kelvins | 0.671709957 ± 5.70953e-06 | K T-1 | |
| 22 | Nuclear magneton | (mu_N) | 5.050786617e-27 ± 1.71727e-33 | J T-1 |
| 23 | Nuclear magneton in eV | 3.1524516628e-08 ± 2.80568e-15 | eV T-1 | |
| 24 | Nuclear magneton in Hz | 7622591.423 ± 2.28678 | T-1 s-1 | |
| 25 | Nuclear magneton in wavenumbers | 0.025426228177 ± 7.62787e-09 | m-1 T-1 | |
| 26 | Nuclear magneton in kelvins | 0.000365824631 ± 3.10951e-09 | K T-1 | |
| 27 | Fine structure constant | (alpha) | 0.0072973530833 ± 3.28381e-10 | |
| 28 | Inverse fine structure constant | 137.035989561 ± 6.16662e-06 | ||
| 29 | Rydberg constant | (Ry) | 10973731.53413 ± 0.0131685 | m-1 |
| 30 | Rydberg constant in Hz | 3.289841949939e+15 ± 3.94781e+06 | s-1 | |
| 31 | Rydberg constant in joules | 2.179874113e-18 ± 1.30792e-24 | J | |
| 32 | Rydberg constant in eV | 13.60569814 ± 4.08171e-06 | eV | |
| 33 | Bohr radius | (a_0) | 5.2917724924e-11 ± 2.3813e-18 | m |
| 34 | Hartree energy | (E_h) | 4.359748226e-18 ± 2.61585e-24 | J |
| 35 | Hartree energy in eV | 27.211396181 ± 8.16342e-06 | eV | |
| 36 | Quantum of circulation | 0.00036369480733 ± 3.23688e-11 | m2 s-1 | |
| 37 | Electron mass | (m_e) | 9.109389754e-31 ± 5.37454e-37 | kg |
| 38 | Electron mass in u | 0.00054857990313 ± 1.26173e-11 | u | |
| 39 | Electron mass in eV | 510999.0615 ± 0.1533 | eV | |
| 40 | Electron-muon mass ratio | 0.0048363321871 ± 7.2545e-10 | ||
| 41 | Electron-proton mass ratio | 0.00054461701311 ± 1.08923e-11 | ||
| 42 | Electron-deuteron mass ratio | 0.0002724437076 ± 5.44887e-12 | ||
| 43 | Electron-alpha-particle mass ratio | 0.0001370933543 ± 2.87896e-12 | ||
| 44 | Electron specific charge | -175881962530 ± -52764.6 | C kg-1 | |
| 45 | Electron molar mass | 5.4857990313e-07 ± 1.26173e-14 | kg mol-1 | |
| 46 | Electron Compton wavelength | (lambda_C) | 2.4263105822e-12 ± 2.15942e-19 | m |
| 47 | Electron Compton wavelength over 2 pi | (lambda-bar_C) | 3.8615932335e-13 ± 3.43682e-20 | m |
| 48 | Electron classical radius | (r_e) | 2.8179409238e-15 ± 3.66332e-22 | m |
| 49 | Electron Thomson cross section | (sigma_e) | 6.652461618e-29 ± 1.79616e-35 | m2 |
| 50 | Electron magnetic moment | 9.284770131e-24 ± 3.15682e-30 | J T-1 | |
| 51 | Electron magnetic moment in Bohr magnetons | 1.0011596521931 ± 1.00116e-11 | ||
| 52 | Electron magnetic moment in nuclear magnetons | 1838.28200037 ± 3.67656e-05 | ||
| 53 | Electron magnetic moment anomaly | (a-e) | 0.0011596521931 ± 9.97301e-12 | |
| 54 | Electron g-factor | (g_e) | 2.0023193043862 ± 2.00232e-11 | |
| 55 | Electron-muon magnetic moment ratio | 206.7669673 ± 3.1015e-05 | ||
| 56 | Electron-proton magnetic moment ratio | 658.210688166 ± 6.58211e-06 | ||
| 57 | Muon mass | 1.883532711e-28 ± 1.14895e-34 | kg | |
| 58 | Muon mass in u | 0.11342891317 ± 1.70143e-08 | u | |
| 59 | Muon mass in eV | 105658389.34 ± 33.8107 | eV | |
| 60 | Muon-electron mass ratio | 206.7682623 ± 3.10152e-05 | ||
| 61 | Muon molar mass | 0.00011342891317 ± 1.70143e-11 | kg mol-1 | |
| 62 | Muon magnetic moment | 4.490451415e-26 ± 1.48185e-32 | J T-1 | |
| 63 | Muon magnetic moment in Bohr magnetons | 0.0048419709771 ± 7.26296e-10 | ||
| 64 | Muon magnetic moment in nuclear magnetons | 8.890598113 ± 1.33359e-06 | ||
| 65 | Muon magnetic moment anomaly | (a_mu) | 0.001165923084 ± 8.39465e-09 | |
| 66 | Muon g-factor | (g_mu) | 2.00233184617 ± 1.68196e-08 | |
| 67 | Muon-proton magnetic moment ratio | 3.1833454747 ± 4.77502e-07 | ||
| 68 | Proton mass | (m_p) | 1.67262311e-27 ± 9.86848e-34 | kg |
| 69 | Proton mass in u | 1.00727647012 ± 1.20873e-08 | u | |
| 70 | Proton mass in eV | 938272312.8 ± 281.482 | eV | |
| 71 | Proton-electron mass ratio | 1836.15270137 ± 3.67231e-05 | ||
| 72 | Proton-muon mass ratio | 8.880244413 ± 1.33204e-06 | ||
| 73 | Proton specific charge | 95788309.29 ± 28.7365 | C kg-1 | |
| 74 | Proton molar mass | 0.00100727647012 ± 1.20873e-11 | kg mol-1 | |
| 75 | Proton Compton wavelength | (lambda_Cp) | 1.3214100212e-15 ± 1.17605e-22 | m |
| 76 | Proton magnetic moment | 1.4106076147e-26 ± 4.79607e-33 | J T-1 | |
| 77 | Proton magnetic moment in Bohr magnetons | 0.00152103220215 ± 1.52103e-11 | ||
| 78 | Proton magnetic moment in nuclear magnetons | 2.79284738663 ± 6.42355e-08 | ||
| 79 | Diamagnetic shielding correction for protons (H_2 O, spherical sample, 298.15 K) | (sigma_H2O) | 2.568915e-05 | |
| 80 | Shielded proton moment (H_2 O, spherical sample, 298.15 K) | (mu_p') | 1.4105713847e-26 ± 4.79594e-33 | J T-1 |
| 81 | Shielded proton moment in Bohr magnetons | 0.00152099312917 ± 1.67309e-11 | ||
| 82 | Shielded proton moment in nuclear magnetons | 2.79277564264 ± 6.42338e-08 | ||
| 83 | Proton gyromagnetic ratio | (gamma_p) | 267522128.81 ± 80.2566 | T-1 s-1 |
| 84 | (gamma_p) | 42577469.13 ± 12.7732 | T-1 s-1 | |
| 85 | Proton gyromagnetic ratio, uncorrected (H_2 O, spherical sample, 298.15 K) | (gamma_p') | 267515255.81 ± 80.2546 | T-1 s-1 |
| 86 | (gamma_p'/2pi) | 42576375.13 ± 12.7729 | T-1 s-1 | |
| 87 | Neutron mass | (m_n) | 1.67492861e-27 ± 9.88208e-34 | kg |
| 88 | Neutron mass in u | 1.00866490414 ± 1.41213e-08 | u | |
| 89 | Neutron mass in eV | 939565632.8 ± 281.87 | eV | |
| 90 | Neutron-electron mass ratio | 1838.6836624 ± 4.0451e-05 | ||
| 91 | Neutron-proton mass ratio | 1.0013784049 ± 9.01241e-09 | ||
| 92 | Neutron molar mass | 0.00100866490414 ± 1.41213e-11 | kg mol-1 | |
| 93 | Neutron Compton wavelength | (lamda_Cn) | 1.3195911012e-15 ± 1.17444e-22 | m |
| 94 | Neutron magnetic moment | 9.66237074e-27 ± 3.96157e-33 | J T-1 | |
| 95 | Neutron magnetic moment in Bohr magnetons | 0.0010418756325 ± 2.5005e-10 | ||
| 96 | Neutron magnetic moment in nuclear magnetons | 1.9130427545 ± 4.5913e-07 | ||
| 97 | Neutron-electron magnetic moment ratio | 0.0010406688225 ± 2.49761e-10 | ||
| 98 | Neutron-proton magnetic moment ratio | 0.6849793416 ± 1.64395e-07 | ||
| 99 | Deuteron mass | (m_d) | 3.34358602e-27 ± 1.97272e-33 | kg |
| 100 | Deuteron mass in u | 2.01355321424 ± 2.41626e-08 | u | |
| 101 | Deuteron mass in eV | 1875613395.7 ± 562.684 | eV | |
| 102 | Deuteron-electron mass ratio | 3670.48301475 ± 7.34097e-05 | ||
| 103 | Deuteron-proton mass ratio | 1.9990074966 ± 5.99702e-09 | ||
| 104 | Deuteron molar mass | 0.00201355321424 ± 2.41626e-11 | kg mol-1 | |
| 105 | Deuteron magnetic moment | (mu_d) | 4.330737515e-27 ± 1.47245e-33 | J T-1 |
| 106 | Deuteron magnetic moment in Bohr magnetons | 0.000466975447991 ± 8.87253e-12 | ||
| 107 | Deuteron magnetic moment in nuclear magnetons | 0.85743823024 ± 2.40083e-08 | ||
| 108 | Deuteron-electron magnetic moment ratio | 0.000466434546091 ± 8.86226e-12 | ||
| 109 | Deuteron-proton magnetic moment ratio | 0.307012203551 ± 5.21921e-09 | ||
| 110 | Avagadro constant | (N_A) | 6.022136736e+23 ± 3.55306e+17 | mol-1 |
| 111 | Atomic mass constant | (m_u) | 1.66054021e-27 ± 9.79719e-34 | kg |
| 112 | Atomic mass constant in eV | 931494322.8 ± 279.448 | eV | |
| 113 | Faraday constant | (F) | 96485.30929 ± 0.0289456 | C mol-1 |
| 114 | Molar Planck constant | 3.9903132336e-10 ± 3.55138e-17 | J s mol-1 | |
| 115 | (N_A hc) | 0.1196265811 ± 1.06468e-08 | J m mol-1 | |
| 116 | Molar gas constant | (R) | 8.3145107 ± 6.98419e-05 | J mol-1 K-1 |
| 117 | Boltzmann constant | (k) | 1.38065812e-23 ± 1.17356e-28 | J K-1 |
| 118 | Boltzmann constant in eV | 8.61738573e-05 ± 7.2386e-10 | eV K-1 | |
| 119 | Boltzmann constant in Hz | 20836741800 ± 175029 | K-1 s-1 | |
| 120 | Boltzmann constant in wavenumbers | 69.5038759 ± 0.000583833 | m-1 K-1 | |
| 121 | Molar volume (ideal gas), STP | (V_m) | 0.0224141019 ± 1.88278e-07 | m3 mol-1 |
| 122 | Loschmidt constant | (n_0) | 2.68676323e+25 ± 2.28375e+20 | m-3 |
| 123 | Stefan-Boltzmann constant | (sigma) | 5.6705119e-08 ± 1.92797e-12 | W m-2 K-4 |
| 124 | First radiation constant | (c_1) | 3.741774922e-16 ± 2.24506e-22 | W m2 |
| 125 | Second radiation constant | (c_2) | 0.0143876912 ± 1.20857e-07 | m K |
| 126 | Wien displacement law constant | (b) | 0.00289775624 ± 2.43412e-08 | m K |
| 127 | Electron volt | (eV) | 1.6021773349e-19 ± 4.80653e-26 | J |
| 128 | Atomic mass unit | (u) | 1.66054021e-27 ± 9.79719e-34 | 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) | 1-1.56350e-6 | Omega |
| 132 | Drift rate of Omega_69-B1 | (dOmega_69-B1/dt) | -0.056615 | muOmega/yr |
| 133 | BIPM-maintained volt 483 694 GHz(h/2e) | (V_76-B1) | 1-7.5930e-6 | V |
| 134 | BIPM maintained ampere A_BIPM | (A_B185) | 1-6.0330e-6 | A |
| 135 | Cu x-unit: | (xu(CuKalpha1)) | 1.002077897e-13 ± 7.01455e-20 | m |
| 136 | Mo x-unit: | (xu(MoKalpha1)) | 1.0020993845e-13 ± 4.50945e-20 | m |
| 137 | AA *: | (AAngstrom-star) | 1.0000148192e-10 ± 9.20014e-17 | m |
| 138 | Lattice spacing of Si (in vacuum, 295.65 K) | (a) | 5.431019611e-10 ± 1.14051e-16 | m |
| 139 | Lattice spacing Si (220) plane | (d_220) | 1.920155404e-10 ± 4.03233e-17 | m |
| 140 | Molar volume of Si | (V_m(Si)) | 1.2058817989e-05 ± 8.92353e-12 | m3 mol-1 |