tools — unit conversion

Magnetic Unit Converter

Magnetics is one of the last engineering fields that still runs on two unit systems at once. Datasheets quote Gauss and MGOe (CGS), simulation tools want Tesla and kJ/m³ (SI), and pull-force specs bounce between pounds, kilograms and newtons. Type a value in any box below — every other unit in that group updates instantly.

flux density — B

Flux density is what a gaussmeter reads and what "surface field" or "Br (residual induction)" refers to on a datasheet. SI unit: tesla. CGS unit: gauss.

gauss ↔ tesla

1 T = 10,000 G · 1 mT = 10 G

gauss (G)

kilogauss

millitesla

tesla (T)

context — N42 NdFeB has a typical Br of ≈ 13,200 G (1.32 T). Earth's field is ≈ 0.5 G (50 µT).

field strength — H

Field strength describes the magnetizing or demagnetizing field, and is the unit behind coercivity values (Hcb, Hcj). SI unit: amperes per meter. CGS unit: oersted.

oersted ↔ kA/m

1 Oe = 1000⁄4π A/m ≈ 79.5775 A/m

oersted (Oe)

kilo-oersted

A/m

kA/m

context — an N42 grade lists Hcj ≥ 12 kOe (≈ 955 kA/m). Higher-temperature suffixes (SH, UH, EH) raise Hcj, not Br.

energy product — (BH)max

The maximum energy product is the figure of merit that names the grade: "N42" means (BH)max ≈ 42 MGOe. SI unit: kilojoules per cubic meter. CGS unit: mega-gauss-oersted.

MGOe ↔ kJ/m³

1 MGOe = 10²⁄4π kJ/m³ ≈ 7.9577 kJ/m³

MGOe

kJ/m³

context — N35 ≈ 279 kJ/m³, N52 ≈ 414 kJ/m³. Ceramic 8 ferrite is ≈ 3.5 MGOe (28 kJ/m³) — about one-twelfth of N42.

supporting units — force & length

Pull-force specs and drawing dimensions are where imperial and metric collide most often in purchasing conversations.

force

1 lbf = 4.44822 N · 1 kgf = 9.80665 N

pounds (lbf)

kilograms (kgf)

newtons (N)

context — our pull force calculator reports all three units for any disc, block or ring in the catalog.

length

1 in = 25.4 mm (exact)

inches (in)

millimeters

context — common fractional sizes: 1/16″ = 1.588 mm, 1/8″ = 3.175 mm, 1/4″ = 6.35 mm, 1/2″ = 12.7 mm, 1″ = 25.4 mm.

magnetic flux

1 Wb = 10⁸ Mx (maxwell)

maxwell (Mx)

microweber

milliweber

context — total flux (measured with a fluxmeter and helmholtz coil) is a common incoming-inspection metric for sensor magnets.

quick reference — conversion factors

Print this page for a bench-side copy. All factors are exact or shown to 6 significant figures.

quantity	cgs unit	si unit	conversion
flux density, B	gauss (G)	tesla (T)	`1 T = 10,000 G` · `1 G = 0.1 mT`
field strength, H	oersted (Oe)	A/m	`1 Oe = 79.5775 A/m` · `1 kA/m = 12.5664 Oe`
energy product, (BH)max	MGOe	kJ/m³	`1 MGOe = 7.95775 kJ/m³`
magnetic flux, Φ	maxwell (Mx)	weber (Wb)	`1 Wb = 10⁸ Mx` · `1 Mx = 0.01 µWb`
force, F	—	newton (N)	`1 lbf = 4.44822 N` · `1 kgf = 9.80665 N` · `1 lbf = 0.453592 kgf`
length	—	meter (m)	`1 in = 25.4 mm` (exact)
permeability of free space, µ₀	1 G/Oe	4π × 10⁻⁷ T·m/A	`µ₀ ≈ 1.25664 × 10⁻⁶ T·m/A`

why B in gauss equals H in oersted inside a vacuum — in the CGS system µ₀ = 1 G/Oe, so B and H are numerically equal in free space. That convenience is why older magnet literature switches between the two without comment, and why SI conversions trip people up: in SI, B = µ₀H introduces the 4π × 10⁻⁷ factor.

usage notes — reading datasheets

Three places unit confusion causes real purchasing mistakes:

surface field vs. Br	Br (≈13,200 G for N42) is a material property measured in a closed circuit. The field you measure at the pole face of an open magnet is far lower — often 2,000–6,000 G depending on geometry. A supplier quoting "13,200 gauss magnets" is quoting Br, not what your sensor will see.
Hcb vs. Hcj	Both are in Oe or kA/m, but Hcj (intrinsic coercivity) is the number that governs demagnetization resistance at temperature. Confirm which one a datasheet lists before comparing grades.
kgf pull ratings	Import datasheets frequently rate pull force in kg. A "10 kg" pot magnet is ≈ 22 lbf — and that rating assumes ideal thick-steel contact. See our pull force calculator for realistic derating.

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