Convert Nanotesla to Milligauss (nT to mG)

Formula

mG = nT ÷ 100

Derivation from SI units:

• 1 nT = 10⁻⁹ T (also called a gamma in geophysics)
• 1 mG = 10⁻³ G = 10⁻⁷ T = 0.1 µT
• 1 nT = 1 × 10⁻⁹ T ÷ 1 × 10⁻⁷ T per mG = 0.01 mG

Both units are defined exactly, so the factor is exact. Nanotesla definition: nanotesla; Milligauss definition: milligauss.

Worked examples

1. A reading of 50 nT converts to 0.5 mG.
   50 nT × 0.01 = 0.5 mG
2. A value of 1000 nT is 10 mG.
   1000 nT × 0.01 = 10 mG

Where it's used

Nanotesla are used for geomagnetic surveys and magnetometers, while milligauss appear in EMF meters for homes and offices. Both measure magnetic flux density (B field), so the conversion is a fixed factor.

Nanotesla to other magnetic flux density units

Frequently asked questions

Sources

• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "gauss".

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.