AWG Wire Gauge Calculator
Convert AWG to diameter/area, and estimate resistance and ampacity.
How it works
The American Wire Gauge (AWG) is a standardized wire gauge system. The cross-sectional area of each AWG size is exactly 20.5% larger than the previous AWG size.
The diameter of any AWG size can be calculated precisely using:
d (mm) = 0.127 × 92^((36 - AWG) / 39)
Resistance is calculated based on standard annealed copper at 20°C (ρ = 1.724×10⁻⁸ Ω·m).
Worked example
For standard 24 AWG hookup wire:
d = 0.127 × 92^((36 - 24) / 39) = 0.5106 mm
Area = π × (d/2)² = 0.2047 mm²
Resistance = 0.017241 / 0.2047 = 84.2 Ω/km.
Frequently Asked Questions
Are these ampacities absolute rules?
No, ampacity depends heavily on the insulation temperature rating (e.g. 60°C, 90°C), ambient temperature, and whether wires are bundled together. The estimates provided are conservative rules of thumb (10A/mm² for chassis wiring in free air, 3A/mm² for power transmission).
Does stranded wire have the same AWG as solid wire?
Yes, AWG specifies the total cross-sectional area of the copper. A stranded 24 AWG wire has the same copper area as a solid 24 AWG wire, but its overall physical diameter will be slightly larger due to the gaps between strands.
Sources
- ASTM B258-02 (Standard for AWG).
- National Electrical Code (NEC) ampacity references.
Results are for engineering assistance. Verify important calculations and check official datasheets. See the Engineering Disclaimer.