Wire Sizing Tool

Wire Gauge Calculator — AWG from Amps

Select the right wire size for your electrical circuit. Enter the load current, wire length (one-way), and voltage to get the minimum AWG or mm² wire gauge with acceptable voltage drop.

Conversion direction

Electrical system

PowerWVoltageV

Quick voltage presets

Calculated result1000 W · 120 V · DC

8.333 A

Formula usedI = P / V

Custom voltage is always supported.

Formulas Used

DCI = P / V

No power factor needed for DC circuits.

AC 1φI = P / (V × PF)

Single-phase AC — multiply voltage by power factor.

AC 3φI = P / (√3 × V × PF)

Three-phase AC — divide by √3 ≈ 1.732.

Frequently Asked Questions

What wire size do I need for 20 amps?

For a 20A circuit, NEC requires #12 AWG copper minimum. For runs longer than 50 feet, consider #10 AWG to limit voltage drop to 3%.

What is the NEC 80% rule for wire sizing?

NEC 310.15 states conductors must be derated to 80% for continuous loads. A #12 AWG wire rated at 20A can carry only 16A continuously.