About this tool
AWG Wire Gauge Calculator is a free, in-browser tool that converts an American Wire Gauge number into the wire's physical and electrical properties. It runs entirely in your browser and uploads nothing.
The diameter follows the AWG definition d = 0.127 mm × 92^((36 − n)/39), where n is the gauge number, so AWG 10 works out to about 2.588 mm. The cross-section area is A = π/4·d², and in thousand-circular-mil units kcmil = A(mm²) × 1.974. Resistance per length uses the material resistivity — copper ρ = 1.724×10⁻⁸ Ω·m, aluminum ρ = 2.82×10⁻⁸ Ω·m — as R/km = ρ / (A·10⁻⁶) × 1000, and R per 1000 ft is that value times 0.3048. The ampacity tile is a rough rule-of-thumb estimate (about 3 A/mm² for power wiring and 8 A/mm² for a single chassis wire in free air), not a code rating.
Use it to pick a wire size, estimate the resistance of a run, or cross-check a datasheet. Remember the AWG scale is inverse: a smaller gauge number means a thicker wire.
Frequently asked questions
How is the wire diameter from a gauge number found?
By the AWG formula d = 0.127 mm × 92^((36 − n)/39), where n is the gauge. Each 6-gauge step roughly halves the diameter, and the scale is inverse — smaller numbers are thicker wires (AWG 10 ≈ 2.588 mm).
How is the resistance per length calculated?
From resistivity: R/km = ρ / (A · 10⁻⁶) × 1000, with A the area in mm² and ρ = 1.724×10⁻⁸ Ω·m for copper or 2.82×10⁻⁸ for aluminum. The Ω/1000 ft figure is the Ω/km value multiplied by 0.3048.
How reliable is the ampacity figure?
It is only a rough guide from a fixed current density (about 3 A/mm² for power runs and 8 A/mm² for a single wire in open air). Real ampacity depends on insulation, ambient temperature, bundling and local electrical code — always check the applicable table before wiring.
Is anything uploaded?
No. The gauge and material are processed locally in your browser; nothing is sent to a server and the tool works offline.
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