Wire Resistance Calculator
Calculate the electrical resistance of a wire by AWG gauge and length. Shows one-way and round-trip resistance.
How It Works
Calculate the electrical resistance of a wire by AWG gauge and length. Shows one-way and round-trip resistance. Enter your values above and click Calculate to get instant results.
Formula
R = ρ × L / A | Simplified: R = resistance_per_kft × length_ft / 1000
Quick Examples
- AWG 12, 100ft → 0.159Ω one-way
- AWG 10, 50m → 0.163Ω one-way
Frequently Asked Questions
Why does wire resistance matter?
Wire resistance causes voltage drop and power loss (heat). Even small resistances become significant at high currents, making proper wire sizing critical.
What is the resistance of copper wire?
Copper resistivity is 1.72×10⁻⁸ Ω·m. AWG 12 copper has about 1.588 Ω per 1000 feet at room temperature.