| Quantity | Symbol | Numerical value | SI unit | Gaussian unit |
|---|---|---|---|---|
| speed of light in vacuum | c | 2.99792458 [2] | ×108 m/s | ×1010 cm/s |
| vacuum magnetic permeability | µ0 | 1.25663706212(19) [3] | ×10-6 N/A2 | - |
| vacuum electric permittivity | ε0 | 8.8541878128(13) [4] | ×10-12 F/m | - |
| vacuum characteristic impedance | Z0 | 376.73031367(6) [5] 4.19169004... [6] |
Ω - |
- ×10-10 s/cm |
| Planck constant | h | 6.62607015 [2] | ×10-34 J s | ×10-27 erg s |
| elementary charge | e | 1.602176634 [2] 4.8032047139(4) |
×10-19 C - |
- ×10-10 statC |
| Josephson constant [7] | KJ | 4.83597848... 1.44978987700(11) |
×1014 Hz/V - |
- ×1017 Hz/statV |
| von Klitzing constant [8] | RK | 25812.8074... 2.8720621651(4) |
Ω - |
- ×10-8 s/cm |
| fine-structure constant | α | 7.2973525693(11) | ×10-3 | ×10-3 |
| Rydberg constant | R∞ | 1.0973731568160(21) | ×107 m-1 | ×105 cm-1 |
| electron mass [9] | me | 9.1093837015(27) | ×10-31 kg | ×10-28 g |
| Bohr magneton [10] | µB | 9.2740100783(28) 9.2740100809(35) |
×10-24 J/T - |
- ×10-21 erg/G |
| atomic mass constant [11] | mu | 1.6605390666(50) | ×10-27 kg | ×10-24 g |
| Avogadro constant | NA | 6.02214076 [2] | ×1023 mol-1 | ×1023 mol-1 |
| Faraday constant [12] | F | 96485.3321... 2.89255748861(22) |
C/mol - |
- ×1014 statC/mol |
| Boltzmann constant | kB | 1.380649 [2] | ×10-23 J/K | ×10-16 erg/K |
| Stefan-Boltzmann constant [13] | σ | 5.67037441... | ×10-8 W/m2 K4 | ×10-33 erg/cm2 s K4 |
| Newtonian constant of gravitation | G | 6.67430(15) | ×10-11 m3/kg s2 | ×10-8 cm3/g s2 |
- Elementary charge:
- Rydberg constant:
[14]
- Electron mass:
[14]
- Bohr magneton:
- Atomic mass constant: