Nominal dimensions · dated reference
A clear view of one wire gauge.
Look up a bare-round AWG diameter in the 1966 NBS table, convert it exactly, and see its approximate geometric cross-section.
Choose the reference gauge
Three different kinds of value
The starting diameter is a rounded nominal table entry. Its unit conversions and circular-mil square are exact arithmetic. Area in mm² uses π and is approximate.
Insulation and strand bundles are outside this model. This tool does not select wire for a circuit or check physical fit.
Read the reference and limitsReference result
- Nominal diameter · mils Exact conversion
- Nominal diameter · inches Exact conversion
- Nominal diameter · millimetres Exact conversion
- Geometric area · circular mils Exact square
- Geometric area · mm² Approximate · 8 significant digits
Why the reference matters
For 40 AWG, the table starts from 3.1 mil, so the exact conversion is 0.07874 mm. An unrounded AWG progression gives a slightly different diameter. Gaugepoint keeps that distinction visible instead of quietly swapping models.
Use the worked examples to check units and the method guide to understand what nominal, exact conversion and approximate area mean here.