Speed of light:

c = 2.998 × 10⁸ m/s

Gravitational constant:

G = 6.668 × 10⁻¹¹ N m² kg⁻²

Planck constant:

h = 6.626 × 10⁻³⁴ J s

   = 4.136 × 10⁻¹⁵ eV s

Boltzmann constant:

k = 1.380 × 10⁻²³ J K⁻¹

   = 8.617 × 10⁻⁵ eV K⁻¹

Stefan–Boltzmann constant:

σ = 5.670 × 10⁻⁸ W m⁻² K⁻⁴

Mass of electron:

m_e = 9.109 × 10⁻³¹ kg

Mass of 1 H atom:

m_H = 1.673 × 10⁻²⁷ kg