American wire gauge (AWG)
The gauge determines the thickness of a wire, and in a geometrical system it may relate to either the diameter or the area of the cross section. Historically, many differing local systems were in use; Birmingham, London, and Lancashire each had their own gauge system. An early geometrical system was introduced by the US tool manufactures Brown & Sharpe in 1855. The Brown & Sharpe gauge is now also known as American wire gauge. This system is in common use throughout Canada and the United States for nonferrous wire.
Standard wire gauge (SWG)
This traditional British measurement system has been in use since 1883, but usage has fallen recently in favour of metric measurements. SWG is also known as Imperial Wire Gauge or British Standard Gauge. It was created by improving upon the older Birmingham wire gauge, and the weight diminishes by 20% between each gauge.
Wire Gauge Chart
| Gauge | SWG | AWG |
| inches | mm | inches | mm |
| 50 | 0.0010 | 0.0254 | 0.00099 | 0.0251 |
| 49 | 0.0012 | 0.0305 | 0.00111 | 0.0282 |
| 48 | 0.0016 | 0.0406 | 0.00124 | 0.0315 |
| 47 | 0.0020 | 0.0508 | 0.00140 | 0.0356 |
| 46 | 0.0024 | 0.0610 | 0.00157 | 0.0399 |
| 45 | 0.0028 | 0.0711 | 0.00176 | 0.0447 |
| 44 | 0.0032 | 0.0813 | 0.00198 | 0.0503 |
| 43 | 0.0036 | 0.0914 | 0.00222 | 0.0564 |
| 42 | 0.0040 | 0.1016 | 0.00249 | 0.0632 |
| 41 | 0.0044 | 0.1118 | 0.00280 | 0.0711 |
| 40 | 0.0048 | 0.1219 | 0.00315 | 0.0800 |
| 39 | 0.0052 | 0.1321 | 0.00353 | 0.0897 |
| 38 | 0.0060 | 0.1524 | 0.00397 | 0.1008 |
| 37 | 0.0068 | 0.1727 | 0.00445 | 0.1130 |
| 36 | 0.0076 | 0.1930 | 0.00500 | 0.1270 |
| 35 | 0.0084 | 0.2134 | 0.00562 | 0.1427 |
| 34 | 0.0092 | 0.2337 | 0.00631 | 0.1603 |
| 33 | 0.0100 | 0.2540 | 0.00708 | 0.1798 |
| 32 | 0.0108 | 0.2743 | 0.00795 | 0.2019 |
| 31 | 0.0116 | 0.2946 | 0.00893 | 0.2268 |
| 30 | 0.0124 | 0.3150 | 0.01000 | 0.2540 |
| 29 | 0.0136 | 0.3454 | 0.01130 | 0.2870 |
| 28 | 0.0149 | 0.3785 | 0.01260 | 0.3200 |
| 27 | 0.0164 | 0.4166 | 0.01420 | 0.3607 |
| 26 | 0.0180 | 0.4572 | 0.01590 | 0.4039 |
| 25 | 0.0200 | 0.5080 | 0.01790 | 0.4547 |
| 24 | 0.0220 | 0.5588 | 0.02010 | 0.5105 |
| 23 | 0.0240 | 0.6096 | 0.02260 | 0.5740 |
| 22 | 0.0280 | 0.7112 | 0.02540 | 0.6452 |
| 21 | 0.0320 | 0.8128 | 0.02850 | 0.7239 |
| 20 | 0.0360 | 0.9144 | 0.03200 | 0.8128 |
| 19 | 0.0400 | 1.0160 | 0.03590 | 0.9119 |
| 18 | 0.0480 | 1.2192 | 0.04030 | 1.0236 |
| 17 | 0.0560 | 1.4224 | 0.04530 | 1.1506 |
| 16 | 0.0640 | 1.6256 | 0.05080 | 1.2903 |
| 15 | 0.0720 | 1.8288 | 0.05710 | 1.4503 |
| 14 | 0.0800 | 2.0320 | 0.06410 | 1.6281 |
| 13 | 0.0920 | 2.3368 | 0.07200 | 1.8288 |
| 12 | 0.1040 | 2.6416 | 0.08080 | 2.0523 |
| 11 | 0.1160 | 2.9464 | 0.09070 | 2.3038 |
| 10 | 0.1280 | 3.2512 | 0.10200 | 2.5908 |
| 9 | 0.1440 | 3.6576 | 0.11400 | 2.8956 |
| 8 | 0.1600 | 4.0640 | 0.12900 | 3.2766 |
| 7 | 0.1760 | 4.4704 | 0.14400 | 3.6576 |
| 6 | 0.1920 | 4.8768 | 0.16200 | 4.1148 |
| 5 | 0.2120 | 5.3848 | 0.18200 | 4.6228 |
| 4 | 0.2320 | 5.8928 | 0.20400 | 5.1816 |
| 3 | 0.2520 | 6.4008 | 0.22900 | 5.8166 |
| 2 | 0.2760 | 7.0104 | 0.25800 | 6.5532 |
| 1 | 0.3000 | 7.6200 | 0.28900 | 7.3406 |
| 0 | 0.3240 | 8.2296 | 0.32500 | 8.2550 |
| 2/0 | 0.3480 | 8.8392 | 0.36500 | 9.2710 |
| 3/0 | 0.3720 | 9.4488 | 0.41000 | 10.4140 |
| 4/0 | 0.4000 | 10.1600 | 0.46000 | 11.6840 |
| 5/0 | 0.4320 | 10.9728 | - | - |
| 6/0 | 0.4640 | 11.7856 | - | - |
| 7/0 | 0.5000 | 12.7000 | - | - |
