AWG to mm² Chart
A printable AWG to mm² conversion chart in PDF: every standard wire size from 4/0 down to 40 AWG with diameter (in / mm), cross-sectional area (kcmil / mm²), and 60 / 75 / 90 °C copper ampacity. Reviewed by a licensed PE.
Download as PDF
Single A4 page, ~ 80 kB, all 26 standard AWG sizes with metric and ampacity columns.
Download PDF (full chart)Need a one-off conversion plus circuit sizing? Use the wire size calculator or browse the full AWG / breaker / conduit / box reference.
The chart — preview
Every standard AWG size with diameter, area, and 75 °C copper ampacity. Full chart (60 / 75 / 90 °C columns) is in the PDF.
| AWG | Ø (in) | Ø (mm) | Area (kcmil) | Area (mm²) | 75 °C Cu (A) |
|---|---|---|---|---|---|
| 4/0 | 0.4600 | 11.68 | 211.6 | 107.2 | 230 |
| 3/0 | 0.4096 | 10.40 | 167.8 | 85.0 | 200 |
| 2/0 | 0.3648 | 9.27 | 133.1 | 67.4 | 175 |
| 1/0 | 0.3249 | 8.25 | 105.6 | 53.5 | 150 |
| 1 | 0.2893 | 7.35 | 83.69 | 42.4 | 130 |
| 2 | 0.2576 | 6.54 | 66.36 | 33.6 | 115 |
| 3 | 0.2294 | 5.83 | 52.62 | 26.7 | 100 |
| 4 | 0.2043 | 5.19 | 41.74 | 21.2 | 85 |
| 6 | 0.1620 | 4.11 | 26.24 | 13.3 | 65 |
| 8 | 0.1285 | 3.26 | 16.51 | 8.37 | 50 |
| 10 | 0.1019 | 2.59 | 10.38 | 5.26 | 35 |
| 12 | 0.0808 | 2.05 | 6.530 | 3.31 | 25 |
| 14 | 0.0641 | 1.63 | 4.107 | 2.08 | 20 |
| 16 | 0.0508 | 1.29 | 2.583 | 1.31 | —* |
| 18 | 0.0403 | 1.02 | 1.624 | 0.823 | —* |
| 20 | 0.0320 | 0.812 | 1.022 | 0.519 | —* |
| 22 | 0.0253 | 0.644 | 0.6424 | 0.326 | —* |
| 24 | 0.0201 | 0.511 | 0.4040 | 0.205 | —* |
| 30 | 0.0100 | 0.255 | 0.1003 | 0.0509 | —* |
| 40 | 0.00314 | 0.0799 | 0.00989 | 0.00501 | —* |
* Sizes 16 AWG and smaller are not listed in NEC 310.16 — use only for fixture / chassis wiring per NEC 402.5. Aluminium ampacity ≈ 0.78 × the copper value at the same temperature column.
Quick conversions
Example 1 — 2.5 mm² UK cable in a US installation. 2.5 mm² is between 13 and 14 AWG. Use 14 AWG (2.08 mm²) for direct dimensional swap; use 12 AWG (3.31 mm²) for ampacity-conservative replacement.
Example 2 — 6 mm² to AWG. 6 mm² ≈ 10 AWG (5.26 mm²). For an EU 6 mm² circuit at 32 A, US 10 AWG copper is rated 35 A at 75 °C — close match.
Example 3 — 50 mm² welding cable. 50 mm² ≈ 1/0 AWG (53.5 mm²). NEC 310.16 ampacity at 75 °C: 150 A.
Example 4 — 24 AWG chassis wire to mm². 24 AWG = 0.205 mm² (0.51 mm Ø). Typical electronics signal wire; not in NEC 310.16 ampacity.
- What is the AWG to mm² formula?
- The American Wire Gauge is a geometric series defined by ASTM B258. Convert AWG number n to diameter in inches: d_n = 0.005 × 92^((36 − n) / 39). Convert diameter to area in kcmil: A = 1 000 × d² (d in inches). Convert kcmil to mm²: A_mm² = A_kcmil × 0.5067. Or skip the math and use the chart on this page — every standard size is precomputed.
- What is the closest AWG to 2.5 mm² (UK / EU)?
- 2.5 mm² ≈ 14 AWG (which is 2.08 mm²). 14 AWG is slightly smaller — about 17 % less area — so for direct UK-to-US replacement use 12 AWG (3.31 mm²) to be conservative on ampacity. Common UK / IEC 60228 sizes and their nearest AWG: 1.5 mm² ≈ 16 AWG, 2.5 mm² ≈ 14 AWG, 4 mm² ≈ 12 AWG, 6 mm² ≈ 10 AWG, 10 mm² ≈ 8 AWG, 16 mm² ≈ 6 AWG, 25 mm² ≈ 4 AWG.
- How do I convert mm² to AWG?
- Reverse-lookup the chart: find your mm² value in the area column and read the AWG number on the same row. Or use the formula: AWG ≈ 36 − 39 × log₁₀(mm² / 0.0127) / log₁₀(92). Round up (smaller AWG number → larger wire) for an electrical-safety-conservative match. The chart on this page lists 26 sizes — every standard AWG from 4/0 (107.2 mm²) to 40 (0.005 mm²).
- Why does smaller AWG number mean bigger wire?
- AWG measures the number of drawing operations through a die that reduce a starting rod to the final diameter. A 4/0 wire (the largest practical AWG) is drawn 0 times — it is the original 0.46-inch rod. A 40 AWG wire (hair-thin) has been drawn through 40 progressively smaller dies. So more drawing operations = thinner wire = higher AWG number. This convention dates from the Brown & Sharpe gauge of 1857.
- Is 4 mm² the same as 12 AWG?
- Close but not identical. 12 AWG = 3.31 mm²; 4 mm² is between 11 and 12 AWG. For ampacity comparisons IEC 60228 4 mm² is rated about 32 A (PVC insulation, 30 °C ambient, single-circuit), while NEC 310.16 12 AWG copper at 75 °C is 25 A. The two standards use different test conditions, so always size in the local standard rather than cross-converting ampacity.
Sources
- ASTM International. ASTM B258-18 — Standard Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors.
- IEC. IEC 60228:2004 — Conductors of insulated cables. The metric mm² conductor-size standard used outside North America.
- NFPA. NFPA 70 — National Electrical Code (2023). Article 310.16 (ampacity), Article 402.5 (fixture wire ampacity).