AWG Wire Size Chart (Gauge to mm, mm² and kcmil)
Every American Wire Gauge size from 4/0 to 40, calculated from the ASTM B258 definition, with copper resistance at 20 °C and the nearest IEC 60228 metric cable size. Current ratings depend on the installation, so use your wiring code for those.
Standards and method
Diameters and areas are calculated from the AWG definition; resistance uses the IEC 60028 copper resistivity; the nearest metric size is the IEC 60228 cross-section closest in area.
Maintained by Miguel Coelho. Updated . See our editorial policy.
Printable AWG wire size chart
American Wire Gauge 4/0 to 40: diameter, area in mm² and kcmil, copper resistance and nearest metric size. Includes the exact definition, formulas, a worked example and sources. Conversion values are checked against the defining constants, and reference data is cited to its source, before the PDF is published.
Free to print, share and use in teaching materials with attribution (CC BY 4.0).
Also in the Electrician and Electronics Reference Pack, with related sheets in one PDF.
Full AWG wire size chart
American Wire Gauge 4/0 to 40: diameter, area in mm² and kcmil, copper resistance and nearest metric size. These are the same tables as the printable PDF. For: Electricians, electronics engineers, installers, makers and students.
- Key relationship
- AWG 36 = 0.005 in and AWG 4/0 = 0.46 in; 39 steps between them (ASTM B258)
- Formula
- d = 0.005 in × 92^((36 − n) ÷ 39)
- Reverse
- n = 36 − 39 × log₉₂(d ÷ 0.005 in)
- Worked example
- AWG 12: 0.0808 in = 2.053 mm, 3.31 mm²
- Rounding
- Solid round copper at 20 °C, 1/58 Ω·mm²/m (IEC 60028). Every 6 gauges halves the diameter; every 3 gauges halves the area.
AWG sizes, dimensions and copper resistance
Nearest metric size is the closest IEC 60228 cross-section by area. It is not a substitute for sizing a cable to your wiring code.
| AWG | Diameter (in) | Diameter (mm) | Area (mm²) | Area (kcmil) | Ω per km | Ω per 1000 ft | Nearest mm² |
|---|---|---|---|---|---|---|---|
| 4/0 (0000) | 0.4600 | 11.684 | 107.2 | 211.6 | 0.1608 | 0.04901 | 120 |
| 3/0 (000) | 0.4096 | 10.405 | 85.03 | 167.8 | 0.2028 | 0.0618 | 95 |
| 2/0 (00) | 0.3648 | 9.266 | 67.43 | 133.1 | 0.2557 | 0.07793 | 70 |
| 1/0 (0) | 0.3249 | 8.251 | 53.48 | 105.5 | 0.3224 | 0.09827 | 50 |
| 1 | 0.2893 | 7.348 | 42.41 | 83.69 | 0.4066 | 0.1239 | 50 |
| 2 | 0.2576 | 6.544 | 33.63 | 66.37 | 0.5127 | 0.1563 | 35 |
| 3 | 0.2294 | 5.827 | 26.67 | 52.63 | 0.6465 | 0.197 | 25 |
| 4 | 0.2043 | 5.189 | 21.15 | 41.74 | 0.8152 | 0.2485 | 25 |
| 5 | 0.1819 | 4.621 | 16.77 | 33.1 | 1.028 | 0.3133 | 16 |
| 6 | 0.1620 | 4.115 | 13.3 | 26.25 | 1.296 | 0.3951 | 16 |
| 7 | 0.1443 | 3.665 | 10.55 | 20.82 | 1.634 | 0.4982 | 10 |
| 8 | 0.1285 | 3.264 | 8.366 | 16.51 | 2.061 | 0.6282 | 10 |
| 9 | 0.1144 | 2.906 | 6.634 | 13.09 | 2.599 | 0.7921 | 6 |
| 10 | 0.1019 | 2.588 | 5.261 | 10.38 | 3.277 | 0.9989 | 6 |
| 11 | 0.0907 | 2.305 | 4.172 | 8.234 | 4.132 | 1.26 | 4 |
| 12 | 0.0808 | 2.053 | 3.309 | 6.53 | 5.211 | 1.588 | 4 |
| 13 | 0.0720 | 1.828 | 2.624 | 5.178 | 6.571 | 2.003 | 2.5 |
| 14 | 0.0641 | 1.628 | 2.081 | 4.107 | 8.286 | 2.525 | 2.5 |
| 15 | 0.0571 | 1.450 | 1.65 | 3.257 | 10.45 | 3.184 | 1.5 |
| 16 | 0.0508 | 1.291 | 1.309 | 2.583 | 13.17 | 4.016 | 1.5 |
| 17 | 0.0453 | 1.150 | 1.038 | 2.048 | 16.61 | 5.064 | 1 |
| 18 | 0.0403 | 1.024 | 0.823 | 1.624 | 20.95 | 6.385 | 0.75 |
| 19 | 0.0359 | 0.912 | 0.6527 | 1.288 | 26.42 | 8.051 | 0.75 |
| 20 | 0.0320 | 0.812 | 0.5176 | 1.022 | 33.31 | 10.15 | 0.5 |
| 21 | 0.0285 | 0.723 | 0.4105 | 0.8101 | 42 | 12.8 | 0.5 |
| 22 | 0.0253 | 0.644 | 0.3255 | 0.6424 | 52.96 | 16.14 | — |
| 23 | 0.0226 | 0.573 | 0.2582 | 0.5095 | 66.79 | 20.36 | — |
| 24 | 0.0201 | 0.511 | 0.2047 | 0.404 | 84.22 | 25.67 | — |
| 25 | 0.0179 | 0.455 | 0.1624 | 0.3204 | 106.2 | 32.37 | — |
| 26 | 0.0159 | 0.405 | 0.1288 | 0.2541 | 133.9 | 40.81 | — |
| 27 | 0.0142 | 0.361 | 0.1021 | 0.2015 | 168.9 | 51.47 | — |
| 28 | 0.0126 | 0.321 | 0.08098 | 0.1598 | 212.9 | 64.9 | — |
| 29 | 0.0113 | 0.286 | 0.06422 | 0.1267 | 268.5 | 81.84 | — |
| 30 | 0.0100 | 0.255 | 0.05093 | 0.1005 | 338.6 | 103.2 | — |
| 31 | 0.0089 | 0.227 | 0.04039 | 0.0797 | 426.9 | 130.1 | — |
| 32 | 0.0080 | 0.202 | 0.03203 | 0.06321 | 538.3 | 164.1 | — |
| 33 | 0.0071 | 0.180 | 0.0254 | 0.05013 | 678.8 | 206.9 | — |
| 34 | 0.0063 | 0.160 | 0.02014 | 0.03975 | 856 | 260.9 | — |
| 35 | 0.0056 | 0.143 | 0.01597 | 0.03152 | 1,079 | 329 | — |
| 36 | 0.0050 | 0.127 | 0.01267 | 0.025 | 1,361 | 414.8 | — |
| 37 | 0.0045 | 0.113 | 0.01005 | 0.01983 | 1,716 | 523.1 | — |
| 38 | 0.0040 | 0.101 | 0.007967 | 0.01572 | 2,164 | 659.6 | — |
| 39 | 0.0035 | 0.090 | 0.006318 | 0.01247 | 2,729 | 831.8 | — |
| 40 | 0.0031 | 0.080 | 0.00501 | 0.009888 | 3,441 | 1,049 | — |
Metric cable sizes (IEC 60228) to AWG
| Area (mm²) | Solid diameter (mm) | Area (kcmil) | Nearest AWG | Ω per km (copper) |
|---|---|---|---|---|
| 0.5 | 0.80 | 0.9868 | 20 | 34.48 |
| 0.75 | 0.98 | 1.48 | 18 | 22.99 |
| 1 | 1.13 | 1.974 | 17 | 17.24 |
| 1.5 | 1.38 | 2.96 | 15 | 11.49 |
| 2.5 | 1.78 | 4.934 | 13 | 6.897 |
| 4 | 2.26 | 7.894 | 11 | 4.31 |
| 6 | 2.76 | 11.84 | 9 | 2.874 |
| 10 | 3.57 | 19.74 | 7 | 1.724 |
| 16 | 4.51 | 31.58 | 5 | 1.078 |
| 25 | 5.64 | 49.34 | 3 | 0.6897 |
| 35 | 6.68 | 69.07 | 2 | 0.4926 |
| 50 | 7.98 | 98.68 | 1/0 (0) | 0.3448 |
| 70 | 9.44 | 138.1 | 2/0 (00) | 0.2463 |
| 95 | 11.00 | 187.5 | 3/0 (000) | 0.1815 |
| 120 | 12.36 | 236.8 | 4/0 (0000) | 0.1437 |
| 150 | 13.82 | 296 | 4/0 (0000) | 0.1149 |
| 185 | 15.35 | 365.1 | 4/0 (0000) | 0.0932 |
| 240 | 17.48 | 473.6 | 4/0 (0000) | 0.07184 |
| 300 | 19.54 | 592.1 | 4/0 (0000) | 0.05747 |
| 400 | 22.57 | 789.4 | 4/0 (0000) | 0.0431 |
| 500 | 25.23 | 986.8 | 4/0 (0000) | 0.03448 |
| 630 | 28.32 | 1,243 | 4/0 (0000) | 0.02737 |
Using this chart
| Point | What to know |
|---|---|
| Stranded wire | A stranded conductor of the same gauge has about the same copper area but a slightly larger overall diameter. |
| Resistance and temperature | Copper resistance rises about 0.393% per °C above 20 °C; at 75 °C it is about 22% higher than shown. |
| Current rating | Ampacity depends on insulation, installation method, bundling and ambient temperature. Use NEC Table 310.16, BS 7671 or IEC 60364-5-52. |
| kcmil and MCM | 1 kcmil = 1,000 circular mils = 0.5067 mm². Sizes above 4/0 are named in kcmil (250, 300, 350 …). |
| Voltage drop | Two-wire drop = 2 × length × current × Ω per unit length. Many codes recommend no more than 3% to 5%. |
Sources for this chart
Diameters and areas are calculated from the AWG definition; resistance uses the IEC 60028 copper resistivity; the nearest metric size is the IEC 60228 cross-section closest in area.
- ASTM B258 — Standard nominal diameters and cross-sectional areas of AWG sizes of solid round wires
- IEC 60028 — International standard of resistance for copper: 1/58 Ω·mm²/m at 20 °C (100% IACS)
- IEC 60228 — Conductors of insulated cables: nominal cross-sectional areas
Related Converters & Charts
AWG Wire Size Chart (Gauge to mm, mm² and kcmil) FAQs
Common questions about the AWG wire size chart.
How thick is 12 AWG wire?
12 AWG solid wire is 0.0808 in (2.053 mm) in diameter with a cross-section of 3.31 mm² (6.53 kcmil). Its copper resistance is about 5.21 Ω per km at 20 °C.
What metric size is closest to 14 AWG?
14 AWG is 2.08 mm², so the nearest IEC 60228 size is 2.5 mm². 12 AWG (3.31 mm²) is nearest to 4 mm², and 10 AWG (5.26 mm²) to 6 mm². Size cables for current to your local wiring code.
Why does a larger AWG number mean a thinner wire?
AWG numbers count drawing steps: each step makes the wire thinner. Every 6 gauges halve the diameter and every 3 gauges halve the cross-sectional area.
Can I download this chart as a PDF, CSV, or JSON?
Yes. Use the Download A4 PDF or US Letter PDF buttons for a printable version, or download the same tables as CSV or JSON from the links on this page.