CONDUCTOR SIZE CONVERSION

AWG ↔ mm² Converter

Convert American Wire Gauge to metric conductor area and back without pretending the two size systems are exact equivalents.

INPUTS

Conversion parameters

Choose the conversion direction. AWG values use the standard geometric gauge series from 4/0 to 40 AWG.

Conversion

Conductor area

mm²

For mm² → AWG the calculator shows both the nearest gauge and the smallest standard AWG area that is not below your target.

Result

READY

Minimum AWG with area ≥ target—

Important: This is a conductor-area conversion, not an ampacity conversion. Do not substitute an AWG conductor for a metric conductor solely from area. Verify the actual cable construction, applicable code/standard, temperature rating, installation method and manufacturer data.

Method

The AWG diameter follows the standard geometric series. Area is then calculated from the nominal solid-wire diameter.

d(mm) = 0.127 × 92^((36 − n)/39)
A = πd² / 4

Why two AWG answers?
“Nearest” minimizes area difference. “Minimum AWG with area ≥ target” never returns a standard AWG cross-sectional area below the entered mm² value.

Why many AWG/mm² tables are misleading

Metric cable sizes such as 1.5, 2.5, 4, 6 and 10 mm² are their own preferred size series. AWG follows a logarithmic geometric progression. Because the series do not line up, an exact one-to-one conversion usually does not exist.

Example: 2.5 mm²

13 AWG has a nominal area of about 2.624 mm², while 14 AWG is about 2.081 mm². Calling 2.5 mm² “14 AWG” understates conductor area by roughly 17%.

Example: 4 mm²

11 AWG is about 4.172 mm² and 12 AWG is about 3.309 mm². A converter should not silently return 12 AWG if the requirement is to meet or exceed 4 mm².

Reference basis

ASTM B258 specifies standard nominal diameters and cross-sectional areas for AWG sizes of solid round electrical conductors. The equations here reproduce that standard AWG geometric series and calculate only at the final step.

Solid versus stranded conductors

The calculated AWG diameter is the nominal diameter of a solid round wire. A stranded cable has interstices, strand lay and possibly compacted construction, so its overall conductor diameter is not obtained from this simple area formula. For cable selection, use the manufacturer’s construction data.

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