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AWG to Inch to Metric Wire Size Conversion Chart

AWG to Metric Conversion Chart
AWG Number Ø [Inch] Ø [mm] Ø [mm²] Resistance [Ohm/m]
4/0 = 0000 0.460 11.7 107 0.000161
3/0 = 000 0.410 10.4 85.0 0.000203
2/0 = 00 0.365 9.26 67.4 0.000256
1/0 = 0 0.325 8.25 53.5 0.000323
1 0.289 7.35 42.4 0.000407
2 0.258 6.54 33.6 0.000513
3 0.229 5.83 26.7 0.000647
4 0.204 5.19 21.1 0.000815
5 0.182 4.62 16.8 0.00103
6 0.162 4.11 13.3 0.00130
7 0.144 3.66 10.5 0.00163
8 0.128 3.26 8.36 0.00206
9 0.114 2.91 6.63 0.00260
AWG Number Ø [Inch] Ø [mm] Ø [mm²] Resistance [Ohm/m]
10 0.102 2.59 5.26 0.00328
11 0.0907 2.30 4.17 0.00413
12 0.0808 2.05 3.31 0.00521
13 0.0720 1.83 2.62 0.00657
14 0.0641 1.63 2.08 0.00829
15 0.0571 1.45 1.65 0.0104
16 0.0508 1.29 1.31 0.0132
17 0.0453 1.15 1.04 0.0166
18 0.0403 1.02 0.823 0.0210
19 0.0359 0.912 0.653 0.0264
AWG Number Ø [Inch] Ø [mm] Ø [mm²] Resistance [Ohm/m]
20 0.0320 0.812 0.518 0.0333
21 0.0285 0.723 0.410 0.0420
22 0.0253 0.644 0.326 0.0530
23 0.0226 0.573 0.258 0.0668
24 0.0201 0.511 0.205 0.0842
25 0.0179 0.455 0.162 0.106
26 0.0159 0.405 0.129 0.134
27 0.0142 0.361 0.102 0.169
28 0.0126 0.321 0.0810 0.213
29 0.0113 0.286 0.0642 0.268
AWG Number Ø [Inch] Ø [mm] Ø [mm²] Resistance [Ohm/m]
30 0.0100 0.255 0.0509 0.339
31 0.00893 0.227 0.0404 0.427
32 0.00795 0.202 0.0320 0.538
33 0.00708 0.180 0.0254 0.679
34 0.00631 0.160 0.0201 0.856
35 0.00562 0.143 0.0160 1.08
36 0.00500 0.127 0.0127 1.36
37 0.00445 0.113 0.0100 1.72
38 0.00397 0.101 0.00797 2.16
39 0.00353 0.0897 0.00632 2.73
40 0.00314 0.0799 0.00501 3.44

One mil is 0.001 inch or one "thou".  Used frequently in measuring very large wire sizes. The circular mil is a unit of area used especially when denoting the cross-sectional size of a wire or cable. It is the equivalent area of a circle whose diameter is 0.001 (10-3) inch, or approximately 0.7854 millionths of a square inch (or 2.5 x 10-7 times pi).

In plane geometry, area always varies in direct proportion to the square of the linear dimension. Thus, if wire A is twice the diameter of wire B, then wire A has four times the cross-sectional area, in circular mils, of B. If wire C is 1/5 of the diameter of wire D, then C has 1/25 the cross-sectional area, in circular mils, of D. In this respect, the circular mil is like any other unit for measurement of area.

MCM is used by wire manufacturers, Kcmil is used by the NEC, both are the same thing. Kcmil is an updated term to bring the NEC up to standards used around the world, so I am told...