Temperature corresponding to 0 °C.
exact

Standard acceleration of gravity.
exact

Standard atmosphere.
exact

Atomic mass unit (unified).
0.59 ppm

Electron volt.
0.030 ppm

Wien displacement law constant, hc/k/4.96511423...
8.4 ppm

Stefan-
Boltzmann constant.
34 ppm

Molar volume (ideal gas), RT/p (at 273.15 K, 101325 Pa).
8.4 ppm

Boltzmann constant.
8.5 ppm

Molar gas constant.
8.4 ppm

Faraday constant.
0.30 ppm

Atomic mass constant.
0.59 ppm

Avogadro constant.
0.59 ppm

Magnetic moment of the neutron.
0.34 ppm
The neutron magnetic dipole is antiparallel to that of the proton.

Compton wavelength of the neutron.
0.089 ppm

Neutron mass in eV.
0.30 ppm

Neutron mass.
0.59 ppm

Magnetic Moment of the proton.
0.34 ppm

Compton wavelength of the proton.
0.089 ppm

Proton mass in eV.
0.30 ppm

Proton mass.
0.59 ppm

g-factor of the muon.
0.0084 ppm

Magnetic moment of the muon.
0.34 ppm

Muon mass in eV.
0.32 ppm

Muon mass.
0.61 ppm

g-factor of the electron.
0.00001 ppm

Magnetic moment of the electron.
0.34 ppm

Compton wavelength of the electron.
0.089 ppm

Electron mass in eV.
0.30 ppm

Electron mass.
0.59 ppm

Bohr radius.
0.045 ppm

Rydeberg constant in eV.
0.30 ppm

Rydeberg constant in joules.
0.60 ppm

Rydeberg constant in hertz.
0.0012 ppm

Rydeberg constant.
0.0012 ppm

Inverse fine structure constant.
0.045 ppm

Nuclear Magneton.
0.34 ppm

Bohr Magneton.
0.34 ppm

Quantized Hall resistance, h/(e^2).
0.045 ppm

Elementary charge.
0.30 ppm



h/(2π).
0.60 ppm



Planck constant.
0.60 ppm

Newtonian constant of gravitation.
128 ppm

Permittivity of vacuum.
exact

Permeability of vacuum.
exact

Speed of light in vacuum.
exact