Physical Constants
The fundamental constants of nature — values, units, and what they mean.
Speed of Light
c = 299,792,458 m/s
Gravitational Constant
G = 6.674×10⁻¹¹ m³/(kg·s²)
Planck Constant
h = 6.62607×10⁻³⁴ J·s
Reduced Planck Constant
ħ = 1.05457×10⁻³⁴ J·s
Elementary Charge
e = 1.602176×10⁻¹⁹ C
Boltzmann Constant
k_B = 1.380649×10⁻²³ J/K
Avogadro Constant
N_A = 6.02214×10²³ 1/mol
Gas Constant
R = 8.314462 J/(mol·K)
Vacuum Permittivity
ε₀ = 8.854187×10⁻¹² F/m
Vacuum Permeability
μ₀ = 1.256637×10⁻⁶ H/m
Electron Mass
m_e = 9.10938×10⁻³¹ kg
Proton Mass
m_p = 1.672621×10⁻²⁷ kg
Stefan–Boltzmann Constant
σ = 5.670374×10⁻⁸ W/(m²·K⁴)
Standard Gravity
g₀ = 9.80665 m/s²
Atmospheric Pressure
atm = 101,325 Pa
Fine-Structure Constant
α = 7.2973525×10⁻³ —
Faraday Constant
F = 96,485.33 C/mol
Rydberg Constant
R∞ = 1.0973731×10⁷ 1/m