Proton g factor = 5.585 694 6893 (dimensionless)

Value
5.585 694 6893
Unit
(dimensionless)
Uncertainty
0.000 000 0016
Copy-ready
5.5856946893

The g-factor of the proton: the dimensionless number linking its magnetic moment to its spin.

Compared with theory as a test of quantum electrodynamics (for leptons) or of nuclear models (for nuclei).

NIST, Fundamental Physical Constants — Complete Listing (2022 CODATA adjustment), retrieved 2026-07-26.

Magnetic moments, g-factors and gyromagnetic ratios

Deuteron magnetic momentElectron magnetic momentElectron g factorElectron gyromagnetic ratioElectron magnetic moment anomalyHelion g factorHelion magnetic momentHelion shielding shiftMuon g factorMuon magnetic momentMuon magnetic moment anomalyNeutron magnetic momentNeutron g factorNeutron gyromagnetic ratioProton g factorProton gyromagnetic ratioProton magnetic momentProton magnetic shielding correctionShielded helion gyromagnetic ratioShielded helion magnetic momentShielded proton gyromagnetic ratioShielded proton magnetic momentShielding difference of d and p in HDShielding difference of t and p in HTTriton g factorTriton magnetic moment

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All physical constants

Constants and formula sheetMagnetic moments, g-factors and gyromagnetic ratiosAll calculators