Wire Gauge Converter Calculator

Work out wire gauge converter instantly with clear inputs, formula shown and shareable results.

About Wire Gauge Converter Calculator

American Wire Gauge is logarithmic and inverted: diameter is 0.127 x 92^((36-n)/39) mm, so larger numbers mean thinner wire and every six gauges halves the area. AWG 12 is 2.05 mm diameter and 3.31 mm2, giving about 0.156 ohms over 30 m of copper and a continuous rating near 20 A.

Formulas

AWG diameter

d(mm) = 0.127 x 92^((36 - n) / 39)

Resistance

R = 0.0172 x length / area, for copper at 20 C

Worked example

With the default values below, Wire Gauge Converter Calculator returns Conductor Diameter of 2.0525. Change any input above and every figure here is recalculated in your browser.

Inputs used

AWG numberaccepts -3–40: 12
Conductor lengthminimum 0 m: 30 m

Results

Conductor Diameter: 2.0525 mm
Cross-Sectional Area: 3.3088 mm2
Resistance Over That Length: 0.1560 ohm
Rough Continuous Current Rating: 19.9 A

Step by step

1Values used
2AWG diameter
3Resistance
4Conductor Diameter= 2.0525 mm
5Cross-Sectional Area= 3.3088 mm2
6Resistance Over That Length= 0.1560 ohm
7Rough Continuous Current Rating= 19.9 A

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does AWG run backwards?

Because it counts drawing operations - each pass through a smaller die raised the gauge number and reduced the diameter.

Is the current rating reliable?

It is a rough 6 A per mm2 guide. Real ampacity depends on insulation type, grouping, ambient temperature and installation method, all set by wiring regulations.