What resistivity value should I use for copper?

Standard annealed copper has a resistivity of about 1.68×10⁻⁸ Ω·m at 20°C. Aluminum is about 2.82×10⁻⁸ Ω·m, roughly 65% more resistive than copper for the same dimensions.

Does temperature affect wire resistance?

Yes, resistance increases with temperature for most conductors. This calculator uses a fixed resistivity value, so results are most accurate near the reference temperature (usually 20°C).

Wire Resistance Calculator

Calculate the DC electrical resistance of a wire based on its length, cross-sectional area, and the resistivity of its material. This is the fundamental formula behind wire gauge selection and voltage drop calculations.

Inputs

Results

Wire Resistance: 0.42 Ω

Try an example

Formula

R = ρ × L / A, where A is cross-sectional area in m²

Learn How This Works

Electrical Engineering Basics: Power Factor, Voltage Drop, and Wire Resistance

How power factor, voltage drop, and wire resistance together determine whether an electrical circuit is sized and configured correctly.

Frequently Asked Questions

Related Calculators

Ohm's Law Calculator

Calculate voltage, current, or resistance using Ohm's Law.

Voltage Drop Calculator

Calculate the voltage drop across a wire or resistive component.

Voltage Divider Calculator

Calculate output voltage of a two-resistor voltage divider circuit.

Electrical Power Calculator

Calculate electrical power from voltage and current.

Simply Supported Beam Deflection Calculator

Calculate maximum deflection of a simply supported beam under a center point load.

Capacitor Energy Calculator

Calculate the energy stored in a charged capacitor.