AWG sizes, 4/0 to 40
American Wire Gauge is a geometric series defined by two anchors: 36 AWG is 0.005 in and 4/0 (0000) is 0.46 in, with 39 equal ratio steps between them. Diameter d = 0.127 mm × 92^((36 − n) ÷ 39), where 4/0 is n = −3, 3/0 is −2, 2/0 is −1 and 0 is 0.
Values below are computed from that definition for solid round wire. Resistance uses annealed copper at 100% IACS (1.7241 × 10⁻⁸ Ω·m at 20 °C). Stranded conductors are slightly larger overall and about 2% higher in resistance.
| AWG | Diameter (in) | Diameter (mm) | Area (mm²) | Area (kcmil) | Copper Ω/km |
|---|---|---|---|---|---|
| 4/0 | 0.4600 | 11.684 | 107.219 | 211.60 | 0.161 |
| 3/0 | 0.4096 | 10.405 | 85.029 | 167.81 | 0.203 |
| 2/0 | 0.3648 | 9.266 | 67.431 | 133.08 | 0.256 |
| 1/0 | 0.3249 | 8.251 | 53.475 | 105.53 | 0.322 |
| 1 | 0.2893 | 7.348 | 42.408 | 83.69 | 0.407 |
| 2 | 0.2576 | 6.544 | 33.631 | 66.37 | 0.513 |
| 3 | 0.2294 | 5.827 | 26.670 | 52.63 | 0.646 |
| 4 | 0.2043 | 5.189 | 21.151 | 41.74 | 0.815 |
| 5 | 0.1819 | 4.621 | 16.773 | 33.10 | 1.028 |
| 6 | 0.1620 | 4.115 | 13.302 | 26.25 | 1.296 |
| 7 | 0.1443 | 3.665 | 10.549 | 20.82 | 1.634 |
| 8 | 0.1285 | 3.264 | 8.366 | 16.51 | 2.061 |
| 9 | 0.1144 | 2.906 | 6.634 | 13.09 | 2.599 |
| 10 | 0.1019 | 2.588 | 5.261 | 10.38 | 3.277 |
| 11 | 0.0907 | 2.305 | 4.172 | 8.23 | 4.132 |
| 12 | 0.0808 | 2.053 | 3.309 | 6.53 | 5.211 |
| 13 | 0.0720 | 1.828 | 2.624 | 5.18 | 6.571 |
| 14 | 0.0641 | 1.628 | 2.081 | 4.11 | 8.285 |
| 15 | 0.0571 | 1.450 | 1.650 | 3.26 | 10.448 |
| 16 | 0.0508 | 1.291 | 1.309 | 2.58 | 13.174 |
| 17 | 0.0453 | 1.150 | 1.038 | 2.05 | 16.612 |
| 18 | 0.0403 | 1.024 | 0.823 | 1.62 | 20.948 |
| 19 | 0.0359 | 0.912 | 0.653 | 1.29 | 26.415 |
| 20 | 0.0320 | 0.812 | 0.518 | 1.02 | 33.308 |
| 21 | 0.0285 | 0.723 | 0.410 | 0.81 | 42.001 |
| 22 | 0.0253 | 0.644 | 0.326 | 0.64 | 52.962 |
| 23 | 0.0226 | 0.573 | 0.258 | 0.51 | 66.784 |
| 24 | 0.0201 | 0.511 | 0.205 | 0.40 | 84.213 |
| 25 | 0.0179 | 0.455 | 0.162 | 0.32 | 106.191 |
| 26 | 0.0159 | 0.405 | 0.129 | 0.25 | 133.904 |
| 27 | 0.0142 | 0.361 | 0.102 | 0.20 | 168.850 |
| 28 | 0.0126 | 0.321 | 0.081 | 0.16 | 212.916 |
| 29 | 0.0113 | 0.286 | 0.064 | 0.13 | 268.482 |
| 30 | 0.0100 | 0.255 | 0.051 | 0.10 | 338.550 |
| 31 | 0.0089 | 0.227 | 0.040 | 0.08 | 426.904 |
| 32 | 0.0080 | 0.202 | 0.032 | 0.06 | 538.315 |
| 33 | 0.0071 | 0.180 | 0.025 | 0.05 | 678.803 |
| 34 | 0.0063 | 0.160 | 0.020 | 0.04 | 855.955 |
| 35 | 0.0056 | 0.143 | 0.016 | 0.03 | 1,079.339 |
| 36 | 0.0050 | 0.127 | 0.013 | 0.03 | 1,361.022 |
| 37 | 0.0045 | 0.113 | 0.010 | 0.02 | 1,716.217 |
| 38 | 0.0040 | 0.101 | 0.008 | 0.02 | 2,164.110 |
| 39 | 0.0035 | 0.090 | 0.006 | 0.01 | 2,728.892 |
| 40 | 0.0031 | 0.080 | 0.005 | 0.01 | 3,441.069 |
SWG (Imperial Standard Wire Gauge)
The British Standard Wire Gauge is a fixed table of diameters rather than a formula. The same gauge number is a different size in SWG and AWG: 14 SWG is 2.032 mm, while 14 AWG is 1.628 mm.
| SWG | Diameter (in) | Diameter (mm) | Area (mm²) |
|---|---|---|---|
| 7/0 | 0.5000 | 12.700 | 126.677 |
| 6/0 | 0.4640 | 11.786 | 109.092 |
| 5/0 | 0.4320 | 10.973 | 94.564 |
| 4/0 | 0.4000 | 10.160 | 81.073 |
| 3/0 | 0.3720 | 9.449 | 70.120 |
| 2/0 | 0.3480 | 8.839 | 61.364 |
| 0 | 0.3240 | 8.230 | 53.192 |
| 1 | 0.3000 | 7.620 | 45.604 |
| 2 | 0.2760 | 7.010 | 38.599 |
| 3 | 0.2520 | 6.401 | 32.178 |
| 4 | 0.2320 | 5.893 | 27.273 |
| 5 | 0.2120 | 5.385 | 22.773 |
| 6 | 0.1920 | 4.877 | 18.679 |
| 7 | 0.1760 | 4.470 | 15.696 |
| 8 | 0.1600 | 4.064 | 12.972 |
| 9 | 0.1440 | 3.658 | 10.507 |
| 10 | 0.1280 | 3.251 | 8.302 |
| 11 | 0.1160 | 2.946 | 6.818 |
| 12 | 0.1040 | 2.642 | 5.481 |
| 13 | 0.0920 | 2.337 | 4.289 |
| 14 | 0.0800 | 2.032 | 3.243 |
| 15 | 0.0720 | 1.829 | 2.627 |
| 16 | 0.0640 | 1.626 | 2.075 |
| 17 | 0.0560 | 1.422 | 1.589 |
| 18 | 0.0480 | 1.219 | 1.167 |
| 19 | 0.0400 | 1.016 | 0.811 |
| 20 | 0.0360 | 0.914 | 0.657 |
| 21 | 0.0320 | 0.813 | 0.519 |
| 22 | 0.0280 | 0.711 | 0.397 |
| 23 | 0.0240 | 0.610 | 0.292 |
| 24 | 0.0220 | 0.559 | 0.245 |
| 25 | 0.0200 | 0.508 | 0.203 |
| 26 | 0.0180 | 0.457 | 0.164 |
| 27 | 0.0164 | 0.417 | 0.136 |
| 28 | 0.0148 | 0.376 | 0.111 |
| 29 | 0.0136 | 0.345 | 0.094 |
| 30 | 0.0124 | 0.315 | 0.078 |
| 31 | 0.0116 | 0.295 | 0.068 |
| 32 | 0.0108 | 0.274 | 0.059 |
| 33 | 0.0100 | 0.254 | 0.051 |
| 34 | 0.0092 | 0.234 | 0.043 |
| 35 | 0.0084 | 0.213 | 0.036 |
| 36 | 0.0076 | 0.193 | 0.029 |
| 37 | 0.0068 | 0.173 | 0.023 |
| 38 | 0.0060 | 0.152 | 0.018 |
| 39 | 0.0052 | 0.132 | 0.014 |
| 40 | 0.0048 | 0.122 | 0.012 |
| 41 | 0.0044 | 0.112 | 0.010 |
| 42 | 0.0040 | 0.102 | 0.008 |
| 43 | 0.0036 | 0.091 | 0.007 |
| 44 | 0.0032 | 0.081 | 0.005 |
| 45 | 0.0028 | 0.071 | 0.004 |
| 46 | 0.0024 | 0.061 | 0.003 |
| 47 | 0.0020 | 0.051 | 0.002 |
| 48 | 0.0016 | 0.041 | 0.001 |
| 49 | 0.0012 | 0.030 | 0.001 |
| 50 | 0.0010 | 0.025 | 0.001 |
Reading the table
Every 3 AWG steps roughly halves or doubles the cross-sectional area, and every 6 steps roughly halves or doubles the diameter. Higher gauge numbers are thinner wires in both systems.
This table does not give ampacity. How much current a conductor may carry depends on its insulation temperature rating, installation method, bundling and the electrical code that applies.