mm to AWG converter: gauge from wire diameter
Measure the wire with calipers, then enter the diameter to find its AWG number.
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How to use it
- Enter wire diameter.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Exact gauge n = 36 − 39 × log(d / 0.127) / log(92), with d in mm. The nearest gauge from 0000 to 40 by diameter is then chosen.
Example
Inputs: Wire diameter = 2 mm. Result: Nearest AWG: 12; Diameter of that gauge: 2.0525 mm; Exact gauge number: 12.22.
Limits and caveats
- Enamel and insulation add to the diameter, so measure bare metal only.
- For stranded wire the outer diameter does not work; use the cross-section instead.
Questions about this tool
What AWG is a 1 mm wire?
The nearest gauge is 18 AWG, which is 1.024 mm.
Why is there a fractional gauge number?
The formula is continuous, so 12.22 means the wire is slightly thinner than 12 AWG.
How do I measure the diameter accurately?
Use calipers or a micrometer on stripped wire and average two readings taken at right angles.