Electrical and electronics
AWG to mm² wire gauge converter
Convert American Wire Gauge to diameter, mm² and circular mils, or mm² and diameter to the matching AWG and the next IEC 60228 size, with copper resistance.
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Result
| AWG | Diameter mm | Diameter in | Area mm² | Area kcmil | Copper Ω/km at 20 °C |
|---|---|---|---|---|---|
| 8 | 3.264 | 0.1285 | 8.366 | 16.51 | 2.061 |
| 9 | 2.906 | 0.1144 | 6.634 | 13.09 | 2.599 |
| 10 | 2.588 | 0.1019 | 5.261 | 10.38 | 3.277 |
| 11 | 2.305 | 0.09074 | 4.172 | 8.234 | 4.132 |
| 12 | 2.053 | 0.08081 | 3.309 | 6.53 | 5.211 |
| 13 | 1.828 | 0.07196 | 2.624 | 5.178 | 6.571 |
| 14 | 1.628 | 0.06408 | 2.081 | 4.107 | 8.285 |
| 15 | 1.45 | 0.05707 | 1.65 | 3.257 | 10.45 |
| 16 | 1.291 | 0.05082 | 1.309 | 2.583 | 13.17 |
Method and limits
ASTM B258 defines AWG geometrically: gauge 36 is 0.005 inch and gauge 0000 (4/0) is 0.46 inch, with 39 steps between them, so dn = 0.005 in × 92(36 − n)/39 (0000 = −3, 000 = −2, 00 = −1, 0 = 0). Area is π d² / 4; a circular mil is the area of a 0.001-inch circle, so the area in circular mils is the diameter in mils squared. Copper resistance uses the IEC 60028 resistivity of annealed copper at 20 °C, 0.017241 Ω·mm²/m.
Worked example: AWG 12 is 2.053 mm (0.0808 in), 3.309 mm² or 6,530 circular mils, 5.21 Ω/km at 20 °C; the next IEC 60228 metric size is 4 mm². AWG 10 is 2.588 mm and 5.261 mm².
From mm² or a diameter, the tool reports the gauge with exactly that area if there is one, otherwise the next larger gauge (smaller number), because a smaller conductor than specified is not a safe substitute.
Limits
Figures are for solid round conductors. Stranded conductors of the same gauge have about the same copper area but a larger overall diameter, and NEC tables list slightly higher stranded resistances. Metric sizes are not exact AWG equivalents; follow your wiring code for substitutions.
References
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