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AWG to mm² converter
Type an AWG size or a cross-section and get the other, plus the diameter, the resistance per kilometre and the typical ampacity. The same numbers sit in the table below, so you can read it without touching the form.
Resistance is for copper at 20 °C (ρ = 0.017241 Ω·mm²/m). Ampacity is typical free-air, single conductor, 30 °C rise — a product standard always overrides it.
Sizing a conductor for a real construction? Send the part number and the run — we confirm the gauge, the resistance limit and what the standard actually requires for that cable.
The table
| AWG | Diameter (mm) | Area (mm²) | Resistance (Ω/km) | Typical ampacity (A) |
|---|---|---|---|---|
| 30 | 0.255 | 0.0509 | 338.5 | 0.142 |
| 28 | 0.321 | 0.0810 | 212.9 | 0.226 |
| 26 | 0.405 | 0.1288 | 133.9 | 0.361 |
| 24 | 0.511 | 0.2047 | 84.2 | 0.577 |
| 22 | 0.644 | 0.3255 | 53.0 | 0.920 |
| 20 | 0.812 | 0.5176 | 33.3 | 1.5 |
| 18 | 1.024 | 0.8230 | 20.9 | 2.3 |
| 16 | 1.291 | 1.3087 | 13.2 | 3.7 |
| 14 | 1.628 | 2.0809 | 8.29 | 5.9 |
| 12 | 2.053 | 3.3088 | 5.21 | 9.3 |
| 10 | 2.588 | 5.2612 | 3.28 | 15 |
| 8 | 3.264 | 8.3656 | 2.06 | 24 |
| 6 | 4.115 | 13.3018 | 1.30 | 37 |
| 4 | 5.189 | 21.1506 | 0.82 | 60 |
| 2 | 6.544 | 33.6308 | 0.51 | 95 |
| 1 | 7.348 | 42.4077 | 0.41 | 130 |
| 1/0 | 8.251 | 53.4751 | 0.32 | 150 |
| 2/0 | 9.266 | 67.4309 | 0.26 | 175 |
| 3/0 | 10.405 | 85.0288 | 0.20 | 200 |
| 4/0 | 11.684 | 107.2193 | 0.16 | 230 |
Reading the two systems
AWG is a geometric series of 39 steps between two diameters, and it runs backwards: a higher number is a thinner wire. Six steps up halves the diameter, three steps up halves the area — which is why 24 AWG is 0.205 mm² and 23 AWG is 0.259 mm², a jump of a quarter in copper.
Metric cable is manufactured in preferred nominal sizes — 0.5, 0.75, 1.0, 1.5, 2.5 mm² — chosen for current-carrying capacity rather than for a geometric series. The two systems therefore never meet exactly: 24 AWG sits between 0.2 and 0.25 mm², and a datasheet that says “0.2 mm²” is describing a slightly thinner conductor than 24 AWG unless it states the diameter.
- Cable category is not a conductor size. CAT6 is usually 23 AWG and CAT5E usually 24 AWG, but a spec that only says “CAT6” leaves the gauge open.
- Resistance scales with area. 23 AWG has 21% less resistance per metre than 24 AWG — that is the whole PoE argument between the two.
- Ampacity is not on the datasheet. Structured cabling is specified by resistance, impedance and loss, not by current rating.
- Stranded conductors measure differently. 24 AWG stranded is 24 AWG of copper in total, not per strand — the strands are finer and the DC resistance slightly higher than solid.