Ohm Circular Mil per Foot (Ω·cmil/ft)
The ohm circular mil per foot is the US wire-table unit of resistivity: the resistance of one foot of wire with a cross-section of one circular mil. Annealed copper is about 10.37 Ω·cmil/ft at 20 °C.
Symbol: Ω·cmil/ft (ASCII: ohm*cmil/ft)
Quantity: electrical resistivity
SI relation: 1 Ω·cmil/ft = 1.662426112525 × 10⁻⁹ Ω·m (exact)
Derivation: 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
Exact: yes, by definition
Typical uses
- US wire tables and AWG calculations
- North American conductor data
Convert ohm circular mils per foot to other units
Open the Electrical Resistivity Converter to convert any value between all units.
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) .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Ohm Circular Mil per Foot (Ω·cmil/ft). Retrieved October 25, 2026, from https://scientificconverters.com/units/ohm-circular-mil-per-foot/
IEEE
Scientific Converters, "Ohm Circular Mil per Foot (Ω·cmil/ft)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/units/ohm-circular-mil-per-foot/