Convert AWG to MM

AWG to MM Conversion Guide

various wire sizes

When selecting and buying electrical cable, many UK and international buyers face difficulty confusion when looking at AWG sizing.

Conversely, when American buyers see mm, confusion reins.

The AWG (American Wire Gauge) system was created by the Brown & Sharpe company and accepted a standard n 1857 and is a logarithmic stepped standardised wire gauge system.

Increasing gauge numbers denote decreasing wire diameter, similar to the British Standard Wire Gauge (SWG).

AWG tables are for a single, solid and round conductor wiht the AWG of a stranded wire determined by the cross sectional area of the equivalent solid conductor. Clearly, due to the small gaps between strands, a stranded wire will always have a slightly larger overall diameter than a solid wire with the same AWG.

Unfortunately AWG does not fit easily into rounded mm or even inches.

To convert between the 2, the n gauge wire diameter dn in millimetres (mm) is equal to 0.127mm times 92 raised to the power of 36 minus gauge number n, divided by 39: dn (mm) = 0.127 mm × 92(36-n)/39.

Good grief.

So, to help you work this out slightly more conveniently, please find the handy conversion below which we have rounded to 2 decimal places.

AWG #Diameter (mm)Diameter (inch)Area (mm2)
0000 (4/0)11.680.46107.22
000 (3/0)10.400.4185.02
00 (2/0)9.270.3667.43
0 (1/0)8.250.3253.48
17.350.2942.41
26.540.2633.63
35.830.2326.67
45.190.2021.15
54.620.1816.77
64.120.1613.30
73.660.1410.55
83.260.138.37
92.910.116.63
102.590.105.26
112.300.094.17
122.050.083.31
131.830.072.62
141.630.062.08
151.450.061.65
161.290.051.31
171.150.051.04
181.020.040.82
190.910.040.65
200.810.030.52
210.720.030.41
220.640.030.32

Be Very Careful!

  • AWG wire gauges run low to high, so the smaller the gauge, the larger it is in mm
  • AWG sizes do not convert perfectly to mm or inches, so be careful especially when rounding down
  • Cable sizes refer to the size of the conductor, not the total thickness of the cable sheathing which can vary widely depending on the material
  • DO NOT confuse AWG with SWG as they are not equal
  • Always double check you a re buying the correct thickness of wire or cable

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