Wire Gauge Chart: AWG to Millimeters and Inches

AWG originated from the number of drawing operations needed to produce a given wire diameter from a thicker stock — fewer operations (a lower number) leaves a thicker wire, while more drawing operations (a higher number) produces progressively thinner wire. This inverse relationship is a historical artifact of the manufacturing process the standard was originally based on.

This chart converts AWG to physical diameter for reference and identification purposes, but wire gauge selection for any electrical installation should be based on your local electrical code's ampacity tables, which account for insulation type, length of run, and installation conditions — not diameter alone. Consult a qualified electrician or your local code for actual wiring decisions.

2.5 mm² is a cable's cross-sectional area, a metric sizing convention, not a diameter, so it doesn't map directly onto this chart's AWG-to-diameter values. A 2.5 mm² conductor has a diameter of about 1.78 mm. That's closest to AWG 13 (1.83 mm) in this table. If your source measurement is a diameter rather than a cross-sectional area, use the diameter columns directly instead.

22 AWG is 0.0253 inches (0.64 mm) in diameter. See the AWG 22 row above.