Convert Ohm Circular Mils per Foot to Microohm Metres

Formula

µΩ·m = Ω·cmil/ft × 0.001662426112525

or µΩ·m = Ω·cmil/ft ÷ 601.5304935757

Derivation from SI units:

• 1 Ω·cmil/ft = (π/4 × (25.4 µm)²) ÷ 0.3048 m Ω ≈ 1.6624 × 10⁻⁹ Ω·m; a circular mil is the area of a 1-mil-diameter circle
• 1 µΩ·m = 10⁻⁶ Ω·m = 1 Ω·mm²/m
• 1 Ω·cmil/ft = 1.662426112525 × 10⁻⁹ Ω·m ÷ 0.000001 Ω·m per µΩ·m = 0.001662426112525 µΩ·m

Both units are defined exactly, so the factor is exact. Ohm Circular Mil per Foot definition: ohm circular mil per foot; Microohm Metre definition: microohm metre.

Worked examples

1. A reading of 16.8 Ω·cmil/ft converts to 0.02792875869 µΩ·m.
   16.8 Ω·cmil/ft × 0.001662426113 = 0.02792875869 µΩ·m
2. A value of 100 Ω·cmil/ft is 0.1662426113 µΩ·m.
   100 Ω·cmil/ft × 0.001662426113 = 0.1662426113 µΩ·m

Where it's used

Ohm Circular Mils per Foot are used for US wire tables and AWG calculations, while microohm metres appear in resistance and heating alloys. Both measure electrical resistivity, so the conversion is a fixed factor.

Ohm Circular Mil per Foot to other electrical resistivity units

Frequently asked questions

Sources

• 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, "circular mil".
• Copper Wire Tables, NBS Handbook 100 (International Annealed Copper Standard), National Bureau of Standards (now NIST) .
• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .

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