Units for magnetic properties

You may also be interested in our common units and conversions page

 SymbolGaussian & cgs emuaConversion factor, CbSI & rationalized mksc
Magnetic flux density, magnetic inductionBgauss (G)d10-4tesla (T), Wb/m2
Magnetic fluxΦmaxwell (Mx), G·cm210-8weber (Wb), volt second (V·s)
Magnetic potential difference, magnetomotive forceU, Fgilbert (Gb)10/4πampere (A)
Magnetic field strength, magnetizing forceHoersted (Oe),e Gb/cm103/4πA/mf
(Volume) magnetizationgMemu/cm3 h103A/m
(Volume) magnetization4πMG103/4πA/m
Magnetic polarization, intensity of magnetizationJ, Iemu/cm34π × 10-4T, Wb/m2 i
(Mass) magnetizationσ, Memu/g1
4π × 10-7
Magnetic momentmemu, erg/G10-3A·m2, joule per tesla (J/T)
Magnetic dipole momentjemu, erg/G4π × 10-10Wb·mi
(Volume) susceptibilityχ, κdimensionless, emu/cm3
(4π)2 × 10-7
henry per meter (H/m), Wb/(A·m)
(Mass) susceptibilityχρ, κρcm3/g, emu/g4π × 10-3
(4π)2 × 10-10
(Molar) susceptibilityχmol, κmolcm3/mol, emu/mol4π × 10-6
(4π)2 × 10-13
Permeabilityµdimensionless4π × 10-7H/m, Wb/(A·m)
Relative permeabilityjµrnot defineddimensionless
(Volume) energy density, energy productkWerg/cm310-1J/m3
Demagnetization factorD, Ndimensionless1/4πdimensionless
  1. Gaussian units and cgs emu are the same for magnetic properties; the defining relation is B = H + 4πM
  2. Multiply a number in Gaussian units by C to convert it to SI (e.g., 1 G × 10-4 T/G = 10-4 T)
  3. SI (Système International d’Unités) has been adopted by the National Bureau of Standards. Where two conversion factors are given, the upper one is recognized under, or consistent with, SI and is based on the definition B = µ0(H + M), where µ0 = 4π × 10-7 H/m. The lower one is not recognized under SI and is based on the definition B = µ0H + J, where the symbol I is often used in place of J.
  4. 1 gauss = 105 gamma (γ)
  5. Both oersted and gauss are expressed as cm-1/2·g1/2·s-1 in terms of base units
  6. A/m was often expressed as “ampere-turn per meter” when used for magnetic field strength
  7. Magnetic moment per unit volume
  8. The designation “emu” is not a unit
  9. Recognized under SI, even though based on the definition B = µ0H + J; see footnote c
  10. µr = µ/µ0 = 1 + χ, all in SI; µr is equal to Gaussian µ
  11. B · H and µ0M · H have SI units J/m3; M · H and B · H/4π have Gaussian units erg/cm3

Goldfarb, R. and Fickett, F. (1985), Units for magnetic properties:, National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NBS.SP.696 (Accessed August 3, 2023)