Electronics CalculatorsHow the sizes are defined
AWG sizes follow a geometric rule: the diameter in millimetres is 0.127 × 92^((36 − n) / 39), with n = −3 for 0000, −2 for 000 and −1 for 00. Each step down in gauge number makes the wire about 12.3 percent thicker, and every six steps double the diameter, approximately. Six gauges lower multiplies the diameter by about 2.0 and the area by about 4.
How the table was checked
The table is calculated with the formula. We compared the diameters of well-known sizes (0000, 000, 00, 0, 1, 2, 10, 14, 18, 20, 24, 30, 36 and 40) with the diameters printed in common references, and all agreed to better than 0.15 percent. The standard, ASTM B258, is a paid document that we did not read.
What the table does not give
It does not give how much current a wire may carry. That depends on insulation, temperature, how the wire is installed and national rules. Use the tables of your local wiring code or the data sheet of the cable.
This is an independent guide. It is not connected with any standards body or company named here. The formulas are the usual textbook ones; the colour code, E-series and AWG values are those printed in common references, because the standards IEC 60062, IEC 60063 and ASTM B258 are paid documents that we did not read. Tables and examples were calculated with Python on 14 November 2026. Check data sheets and local safety rules before you build.