Reference · updated 10 November 2026
AWG to mm2: wire gauge table
AWG is the American Wire Gauge: a lower number is a thicker wire. This page converts AWG to millimetres and to cross-section in mm2, and gives the DC resistance of solid copper for each size. Every value in the tables below is calculated by the formula in the next section; none is typed in by hand.
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AWG to mm2 table
| AWG | Diameter (mm) | Cross-section (mm²) | Resistance (Ω/km, copper, 20 °C) |
|---|---|---|---|
| 0000 (4/0) | 11.684 | 107 | 0.161 |
| 000 (3/0) | 10.405 | 85.0 | 0.203 |
| 00 (2/0) | 9.266 | 67.4 | 0.256 |
| 0 (1/0) | 8.251 | 53.5 | 0.322 |
| 1 | 7.348 | 42.4 | 0.407 |
| 2 | 6.544 | 33.6 | 0.513 |
| 3 | 5.827 | 26.7 | 0.646 |
| 4 | 5.189 | 21.2 | 0.815 |
| 5 | 4.621 | 16.8 | 1.03 |
| 6 | 4.115 | 13.3 | 1.30 |
| 7 | 3.665 | 10.5 | 1.63 |
| 8 | 3.264 | 8.37 | 2.06 |
| 9 | 2.906 | 6.63 | 2.60 |
| 10 | 2.588 | 5.26 | 3.28 |
| 11 | 2.305 | 4.17 | 4.13 |
| 12 | 2.053 | 3.31 | 5.21 |
| 13 | 1.828 | 2.62 | 6.57 |
| 14 | 1.628 | 2.08 | 8.29 |
| 15 | 1.450 | 1.65 | 10.4 |
| 16 | 1.291 | 1.31 | 13.2 |
| 17 | 1.150 | 1.04 | 16.6 |
| 18 | 1.024 | 0.823 | 20.9 |
| 19 | 0.912 | 0.653 | 26.4 |
| 20 | 0.812 | 0.518 | 33.3 |
| 21 | 0.723 | 0.410 | 42.0 |
| 22 | 0.644 | 0.326 | 53.0 |
| 23 | 0.573 | 0.258 | 66.8 |
| 24 | 0.511 | 0.205 | 84.2 |
| 25 | 0.455 | 0.162 | 106 |
| 26 | 0.405 | 0.129 | 134 |
| 27 | 0.361 | 0.102 | 169 |
| 28 | 0.321 | 0.0810 | 213 |
| 29 | 0.286 | 0.0642 | 268 |
| 30 | 0.255 | 0.0509 | 339 |
| 31 | 0.227 | 0.0404 | 427 |
| 32 | 0.202 | 0.0320 | 538 |
| 33 | 0.180 | 0.0254 | 679 |
| 34 | 0.160 | 0.0201 | 856 |
| 35 | 0.143 | 0.0160 | 1079 |
| 36 | 0.127 | 0.0127 | 1361 |
| 37 | 0.113 | 0.0100 | 1716 |
| 38 | 0.101 | 0.00797 | 2164 |
| 39 | 0.0897 | 0.00632 | 2729 |
| 40 | 0.0799 | 0.00501 | 3441 |
How the numbers are calculated
The diameter of a solid round conductor follows from the AWG number n:
d = 0.127 mm × 92^((36 − n) / 39)
The gauges 0000, 000, 00 and 0 (also written 4/0, 3/0, 2/0 and 1/0) count as n = −3, −2, −1 and 0. The cross-section is the area of the circle, A = π/4 × d². For resistance the table uses annealed copper at 20 °C, 17.241 nΩ·m, so R = 17.241 nΩ·m ÷ A.
Three values to check against any other chart: AWG 10 is 2.588 mm and 5.26 mm2, AWG 12 is 2.053 mm and 3.31 mm2, and AWG 24 is 0.511 mm and 0.205 mm2.
What the table is not: it is the size of a solid copper conductor, not a current rating. How much current a wire may carry depends on insulation, bundling, temperature and the rules that apply to your installation. Real conductors are usually stranded or plated, and read a little higher in resistance than the solid-copper figure. Use your drawing, your manual or the applicable code for limits.
Metric sizes and the nearest AWG
AWG and metric sizes do not line up one to one. This table picks, for each common metric cross-section, the AWG whose area is closest. The last column shows how far that AWG is from the metric size.
| Metric size (mm²) | Nearest AWG | Area of that AWG (mm²) | Difference |
|---|---|---|---|
| 0.25 | 23 | 0.258 | +3.3 % |
| 0.5 | 20 | 0.518 | +3.5 % |
| 0.75 | 18 | 0.823 | +9.7 % |
| 1 | 17 | 1.04 | +3.8 % |
| 1.5 | 15 | 1.65 | +10.0 % |
| 2.5 | 13 | 2.62 | +5.0 % |
| 4 | 11 | 4.17 | +4.3 % |
| 6 | 9 | 6.63 | +10.6 % |
| 10 | 7 | 10.5 | +5.5 % |
| 16 | 5 | 16.8 | +4.8 % |
| 25 | 3 | 26.7 | +6.7 % |
| 35 | 2 | 33.6 | −3.9 % |
| 50 | 0 (1/0) | 53.5 | +7.0 % |
| 70 | 00 (2/0) | 67.4 | −3.7 % |
| 95 | 000 (3/0) | 85.0 | −10.5 % |
| 120 | 0000 (4/0) | 107 | −10.7 % |
A positive difference means the AWG wire is larger than the metric size, a negative one means smaller. When the wire carries current, take the next size up when in doubt, and check it against the current rating, not against this table.
Worked examples
From AWG to mm2. A datasheet calls for AWG 12. The table gives 2.053 mm diameter and 3.31 mm2. That falls between the metric sizes 2.5 mm2 and 4 mm2.
Resistance of a run. A solid AWG 20 conductor is 33.3 Ω/km. Over 5 m (0.005 km) that is 33.3 × 0.005 = 0.167 Ω at 20 °C. A reading of 0.167 Ω is small next to the resistance of a pair of test leads, so zero the leads first (see the next section).
From a measured diameter to AWG. You measure a bare solid wire with a micrometer and get 1.02 mm. The closest row is AWG 18 at 1.024 mm, which is 0.823 mm2. Measure bare copper without the insulation, since the table lists the conductor only.
Read this live with a meter
To check a real conductor against the table, connect a Bluetooth multimeter the app reads live, such as the OWON OW18B, and set it to ohms. Short the two probes together and press REL, so the lead resistance is taken off every reading. Then measure the conductor and compare the reading with the Ω/km value above, scaled to the length.
The calculator in the app has preset formulas for Ohm's law and power, series and parallel, dividers, LED resistors, RC, dB and unit conversion, and Cal Box fills it from your live reading and recent captures. The app does not have a wire-gauge table of its own today; this page is the reference. For a full harness check with limits per conductor, see the wire harness continuity test.
What the app does here, and what it doesn't
| What it does | Plan |
|---|---|
| REL shows the difference from a stored reference, for example to null out test-lead resistance. | Free |
| A calculator with SI prefix keys, engineering input such as 4k7 and a parallel operator. | Free |
| Presets for Ohm's law and power, series and parallel, dividers, LED resistors, RC, dB and unit conversion. | Free |
| Cal Box fills the calculator from your live reading and recent captures, and suggests Ohm's law. | Free |
Questions
How do I convert AWG to mm2?
Look up the AWG number in the table and read the cross-section column. Or calculate it: the diameter is 0.127 mm × 92^((36 − n) / 39), and the cross-section is π/4 × d². AWG 10 is 5.26 mm2 and AWG 24 is 0.205 mm2.
Is AWG the same as mm2?
No. AWG is a gauge number for the diameter, and a higher number means a thinner wire. mm2 is the cross-section area. Metric cable sizes such as 1.5 mm2 and 2.5 mm2 do not match a whole AWG number, which is why the second table gives the nearest one.
Which AWG is 1.5 mm2 and 2.5 mm2?
The nearest AWG to 1.5 mm2 is AWG 15 (1.65 mm2), and to 2.5 mm2 it is AWG 13 (2.62 mm2). Both AWG sizes are slightly larger than the metric size. Check the current rating for your wire type before you swap one for the other.
Why is my measured resistance higher than the table?
The table is for solid copper at 20 °C. Stranded wire, tin or silver plating, a warm conductor and the resistance of your test leads all add to the reading. Zero the leads with REL, and keep the conductor at room temperature for a fair comparison.
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