AWG Wire Gauge Calculator

Look up an American Wire Gauge size's diameter, cross-section, and copper resistance — or find the nearest AWG for a given wire diameter. Runs locally in your browser.

AWG number

1–40, or 0 / 00 / 000 / 0000 (1/0 to 4/0)

Enter an AWG number.

The American Wire Gauge system sizes solid round wire by the formula d = 0.005 in × 92^((36−n)/39), where n is the gauge number — bigger numbers mean thinner wire (40 AWG is hair-fine; 4/0 is thick cable). Every 3-gauge step roughly halves the cross-section and doubles the resistance. The resistance values use copper's resistivity at 20 °C (1.724 × 10⁻⁸ Ω·m): R/km ≈ 17.24 ÷ area_mm² and R/1000ft ≈ 5.25 ÷ area_mm². Ampacity depends on insulation rating, bundling, and ambient temperature and is not shown here. Runs locally — nothing leaves your browser.