AWG Wire Gauge Calculator
Enter an American Wire Gauge (AWG) number to find the conductor diameter, cross-sectional area and DC resistance per kilometre for solid copper wire.
How to use the wire gauge calculator
- Enter the AWG number printed on the wire or spec sheet.
- Read the diameter in millimetres and the cross-sectional area in square millimetres.
- Check the copper resistance per kilometre to size a run for voltage drop.
Examples
AWG 12 power wire
awg = 12
diameter 2.05 mm, area 3.31 mm2, 5.08 ohm/km
AWG 24 signal wire
awg = 24
diameter 0.51 mm, area 0.20 mm2
Frequently asked questions
What is the AWG to diameter formula?
Diameter in mm equals 0.127 x 92^((36 - AWG) / 39). Each six-gauge step roughly halves or doubles the diameter.
Does a higher AWG number mean thicker or thinner wire?
Thinner. AWG is an inverse scale, so AWG 24 is much thinner than AWG 12. Very thick wires use 0, 00, 000 and 0000.
How is the resistance per km calculated?
From R = rho x length / area, using copper resistivity of 1.68 x 10^-8 ohm-metres and the wire's cross-sectional area for a solid conductor.
Why does my stranded wire read a slightly different resistance?
This calculator assumes a solid copper conductor at 20 C. Stranded wire and higher temperatures raise the resistance a little above these values.
What does cross-sectional area tell me?
Area in square millimetres sets the current-carrying capacity. A larger area carries more current with less heating and less voltage drop.
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