Wire Gauge Calculator

The Wire Gauge Calculator converts between American Wire Gauge (AWG) labels, wire diameter in millimeters, and cross-sectional area in square millimeters, and reports copper resistance and chassis-wiring ampacity. It supports the full AWG range from 0000 (4/0) down to AWG 40. Lookup works in any direction: enter a gauge, a diameter in mm, or an area in mm², and it finds the closest standard AWG entry.

1. Set Input Type to AWG Gauge, Diameter (mm), or Cross-section (mm²). 2. Provide the input value — pick from the AWG 0000–40 dropdown for gauge, or type a positive number for diameter/area. 3. Click Calculate. The result shows five cards: AWG gauge, Diameter in mm and inches, Cross-section in mm², Resistance in ohm/km, and Ampacity. Click Clear to reset to the AWG 12 default.

Diameter in mm is derived from the AWG definition: 0.127 × 92^((36 − awgNum) / 39), where awgNum is −3 for 0000, −2 for 000, −1 for 00, 0 for 0, and the gauge number itself for 1–40. Cross-section = π × (diameter/2)². Copper resistance at 20 °C uses resistivity 0.017241 ohm·mm²/m, giving ohm/km = 0.017241 / area × 1000. Ampacity is estimated by exponential interpolation across known chassis-wiring data points (for example AWG 12 ≈ 41 A, AWG 14 ≈ 32 A, AWG 10 ≈ 55 A).