| Description | Symbol | Value | Units |
| Acceleration due to gravity | $\mathrm{g}$ | $9.80665 $ | $\mathrm{m/s^2}$ |
| Standard atmosphere | $\mathrm{atm}$ | $101325 $ | $\mathrm{N/m^2}$ |
| Thermochemical kilocalorie | $\mathrm{kcal}$ | $4184$ | $\mathrm{J}$ |
| Speed of light in vacuum | $\mathrm{c}$ | $2.997925 \times 10^8$ | $\mathrm{m/s}$ |
| Electronic charge | $\mathrm{e}$ | $1.6022 \times 10^{-19}$ | $\mathrm{C}$ |
| Electron charge/mass | $\mathrm{e / m_e}$ | $1.76 \times 10^{11}$ | $\mathrm{C/kg}$ |
| Permeability of free space | $\mu_\mathrm{o}$ | $1.26 \times 10^{-6}$ | $\mathrm{H/m}$ |
| Permittivity of free space | $\epsilon_\mathrm{o}$ | $8.8542 \times 10^{-12} $ | $\mathrm{C^2N^{-1}m^{-2}}$ |
| Avogadro constant | $\mathrm{N_A}$ | $6.0225 \times 10^{26}$ | $\mathrm{kmol^{-1}}$ |
| Faraday constant | $\mathrm{F}$ | $9.6487 \times 10^7 $ | $\mathrm{C/kmol}$ |
| Rydberg constant | $\mathrm{R}$ | $1.0974 \times 10^7 $ | $\mathrm{m^{-1}}$ |
| Planck constant | $\mathrm{h}$ | $6.6262 \times 10^{-34} $ | $\mathrm{Js}$ |
| $4.1356 \times 10^{-15}$ | $\mathrm{eV s}$ | ||
| Bohr magneton ($\mathrm{eh}/4\pi \mathrm{m}_e$) | $\mu_\mathrm{B}$ | $9.2732 \times 10^{-24}$ | $\mathrm{Am^2}$ |
| Nuclear magneton ($\mathrm{e}\mathrm{h}/4\pi \mathrm{m}_p$) | $\mu_\mathrm{N}$ | $5.0505 \times 10^{-27}$ | $\mathrm{Am^2}$ |
| Universal gas constant | $\mathrm{R}$ | $8314$ | $\mathrm{JK/kmol}$ |
| $1.987 $ | $\mathrm{kcal\;K/kmol}$ | ||
| Ideal gas normal volume (STP) | $22.414$ | $\mathrm{m^3/kmol}$ | |
| Boltzmann constant | $\mathrm{k}$ | $1.3805 \times 10^{-23} $ | $\mathrm{J/K}$ |
| Wien displacement constant | $\mathrm{A}$ | $2.8978 \times 10^{-3}$ | $\mathrm{mK}$ |
| Stefan-Boltzmann constant | $\sigma$ | $5.670 \times 10^{-8}$ | $\mathrm{Wm^2/K^4}$ |
| Gravitational constant | $\mathrm{G}$ | $6.67 \times 10^{-11}$ | $\mathrm{N m^2/kg^2}$ |
| Atomic mass unit | $\mathrm{amu}$ | $1.6604 \times 10^{-27}$ | $\mathrm{kg}$ |
| Rest energy of 1 amu | $931.48$ | $\mathrm{MeV}$ | |
| Electron volt | $\mathrm{eV}$ | $1.60210 \times 10^{-19}$ | $\mathrm{J}$ |
| Rest mass of electron | $\mathrm{m_e}$ | $5.48597 \times 10^{-4}$ | $\mathrm{amu}$ |
| $9.1095 \times 10^{-31}$ | $\mathrm{kg}$ | ||
| 0.511006 | $\mathrm{MeV}$ | ||
| Rest mass of proton | $\mathrm{m_p}$ | 1.0072766 | $\mathrm{amu}$ |
| $ 1.6726 \times 10^{-27}$ | $\mathrm{kg}$ | ||
| $938.26$ | $\mathrm{MeV}$ |