The following table lists a number of Fundamental Physical Constants. However, it is not intended as a definitive list nor are any of the values guaranteed to be correct or show the correct degree of accuracy. This table lists the most common constants and the units associated with each. Other sources of information on constants are listed in the External Links page.

Constant Value Units Definition Astronomical Unit AU 1.495 978 7 e11 m Mean Sun-Earth distance Alpha 7.297 352 81 e-03 µ0 c e2/h Fine Structure Constant AMU Chemical 1.660 260 00 e-27 kg 1/16 of the weighted average mass of the 3 naturally occuring neutral isotopes of oxygen. AMU Physical 1.659 810 00 e-27 kg 1/16 of the mass of a neutral oxygen 16 atom. Atomic Mass Unit 1.660 540 2 e-27 kg Atomic mass unit (defined to be 1/12 of the mass of carbon 12) Avogadro Number NA 6.022 136 7 e23 particles/mol Number of particles in 1 mole of substance Bohr Radius a0 5.291 772 1 e-11 alpha/pi R   Boltzman Constant k 1.380 658 e-23 J/K Boltzmann constant Coulomb Constant 6.954 063 e-12 pi epsilon0 Listed as "k" sometimes Dalton 1.660 540 2 e-27 µ   Electron Rest Mass me 9.109 389 7 e-31 kg Particle mass Proton Rest Mass mp 1.672 623 1 e-27 kg Particle mass Neutron Rest Mass mn 1.674 928 6 e-27 kg Particle mass Muon Rest Mass mm 1.883 532 7 e-28 kg Particle mass Deuteron Rest Mass md 3.343 586 e-27 kg Particle mass Electron rest energy mec2 8.187 111 2 e-14 J   Elementary Charge e 1.602 177 3 e-19 C Elementary charge Electron Charge-Mass ratio e/me 1.758 819 6 e11 C/kg   Energy 8.987 551 8 e16 c2 Convert mass to energy Faraday Constant F 9.648 46 e4 NA e   Fine Structure Constant (alpha) 7.297 352 81 e-3 µ0 c e2/h Fine Structure Constant Gravitational Constant 6.687 3 e-11 N m2/kg2 Newtonian gravity constant Gas Constant R 8.314 51 J/mol K Molar gas constant Hartree 2.625 501 e6 J/mol Atomic energy unit =  e2/(4 pi epsilon0a0) Light Speed 2.997 924 58 e8 m/s   Molar Volume 2.241 41 e-2 m3/kmol Volume occupied by one mole of an ideal gas at standard temperatureand pressure. Mole 1.0 mol Amount of substance of a system which contains as many elementary entities as atoms in 0.012 kg of unbound carbon 12 atoms, at rest and in the ground state. PI 3.141 592 7 pi   Permeability of vacuum µ0 1.256 637 06 e-6 T2 m2/J   Permittivity of vacuum (epsilon0) 8.854 187 817 e-12 C2/Jm Permittivity of vacuum, epsilon0 = 1/(µ0c2) (exact) Planck Constant h 6.626 075 5 e-34 J s Action of one joule over one second Prout 2.972 04 e-14 keV Nuclear binding energy equal to 1/12 binding energy of the deuteron Rydberg Constant R 1.097 373 2 e7 /m   Speed of Light c 2.997 924 58 e8 m/s Speed of light in vacuo (exact) Standard Temperature 2.731 5 e2 K Standard temperature Unified Mass Unit 1.660 43 e-27 kg