TOOLS
Convert AWG wire gauge to conductor diameter in mm and cross-section in mm2 (mm²), or enter a diameter or area and find the nearest standard AWG and IEC 60228 metric size. Includes kcmil and circular mils.
Conductor Diameter
0.8118 mm
0.03196 in
Values are for a bare solid conductor per ASTM B258. Stranded wire of the same AWG has a slightly larger overall diameter.
Equivalent AWG
20 AWG
Exact equivalent of the combined cross section
Wires Needed
—
Combining wires matches conductor cross section (current capacity), not the overall bundle diameter. Paralleled wires share current evenly only when their gauge, length, and terminations match, and bundled conductors also derate thermally.
Imperial Length
0.3937 in
Inches Fraction 25/64 in 0.08 mm under
Inches Fraction picks the closest fraction on a 1/64 inch grid and simplifies it, and the deviation shows how far that fraction sits from the exact value. Pick 1/8, 1/16 or 1/32 to see the nearest coarser fraction instead. The tape measure row uses 1/16 by default and always reduces to the simplest form.
This calculator provides engineering guidance only. AWG values describe bare solid conductors, so verify stranded constructions and critical dimensions against the manufacturer datasheet.
quick guide
Enter any one value (gauge, diameter, or cross-section) and the other two update instantly.
1. Pick an AWG gauge from 0000 (4/0) to 50 — diameter and cross-section appear immediately.
2. Or type a diameter (mm or inch) or an area (mm², kcmil, cmil) to convert in the other direction.
3. Read the results: diameter in mm and inches, cross-section in mm² and circular mils, the nearest standard AWG, and the nearest IEC 60228 metric size.
4. Paste values straight from a datasheet — “14 AWG”, “2.5 mm”, “0.75 mm²” or “1,022 cmil” are recognized and routed to the right field automatically.
The full AWG to mm² chart from 0000 (4/0) down to 40 AWG. Every value is calculated from the ASTM B258 formula the calculator above uses, for a bare solid round conductor. The last column shows the closest standard metric cross-section, so you can match an AWG wire to its nearest IEC 60228 equivalent.
| AWG | Area (mm²) | Diameter (mm) | Diameter (inch) | Circular mils (kcmil) | Nearest IEC 60228 size (mm²) |
|---|---|---|---|---|---|
| 0000 (4/0) | 107.2193 | 11.6840 | 0.4600 | 211,600 (211.600) | 95 |
| 000 (3/0) | 85.0288 | 10.4049 | 0.4096 | 167,806 (167.806) | 95 |
| 00 (2/0) | 67.4309 | 9.2658 | 0.3648 | 133,077 (133.077) | 70 |
| 0 (1/0) | 53.4751 | 8.2515 | 0.3249 | 105,535 (105.535) | 50 |
| 1 | 42.4077 | 7.3481 | 0.2893 | 83,693 (83.693) | 35 |
| 2 | 33.6308 | 6.5437 | 0.2576 | 66,371 (66.371) | 35 |
| 3 | 26.6705 | 5.8273 | 0.2294 | 52,635 (52.635) | 25 |
| 4 | 21.1506 | 5.1894 | 0.2043 | 41,741 (41.741) | 25 |
| 5 | 16.7732 | 4.6213 | 0.1819 | 33,102 (33.102) | 16 |
| 6 | 13.3018 | 4.1154 | 0.1620 | 26,251 (26.251) | 16 |
| 7 | 10.5488 | 3.6649 | 0.1443 | 20,818 (20.818) | 10 |
| 8 | 8.3656 | 3.2636 | 0.1285 | 16,510 (16.510) | 10 |
| 9 | 6.6342 | 2.9064 | 0.1144 | 13,093 (13.093) | 6 |
| 10 | 5.2612 | 2.5882 | 0.1019 | 10,383 (10.383) | 6 |
| 11 | 4.1723 | 2.3048 | 0.0907 | 8,234 (8.234) | 4 |
| 12 | 3.3088 | 2.0525 | 0.0808 | 6,530 (6.530) | 4 |
| 13 | 2.6240 | 1.8278 | 0.0720 | 5,178 (5.178) | 2.5 |
| 14 | 2.0809 | 1.6277 | 0.0641 | 4,107 (4.107) | 2.5 |
| 15 | 1.6502 | 1.4495 | 0.0571 | 3,257 (3.257) | 1.5 |
| 16 | 1.3087 | 1.2908 | 0.0508 | 2,583 (2.583) | 1.5 |
| 17 | 1.0378 | 1.1495 | 0.0453 | 2,048 (2.048) | 1 |
| 18 | 0.8230 | 1.0237 | 0.0403 | 1,624 (1.624) | 0.75 |
| 19 | 0.6527 | 0.9116 | 0.0359 | 1,288 (1.288) | 0.75 |
| 20 | 0.5176 | 0.8118 | 0.0320 | 1,022 (1.022) | 0.5 |
| 21 | 0.4105 | 0.7229 | 0.0285 | 810 (0.810) | 0.34 |
| 22 | 0.3255 | 0.6438 | 0.0253 | 642 (0.642) | 0.34 |
| 23 | 0.2582 | 0.5733 | 0.0226 | 509 (0.509) | 0.25 |
| 24 | 0.2047 | 0.5106 | 0.0201 | 404 (0.404) | 0.25 |
| 25 | 0.1624 | 0.4547 | 0.0179 | 320 (0.320) | 0.14 |
| 26 | 0.1288 | 0.4049 | 0.0159 | 254 (0.254) | 0.14 |
| 27 | 0.1021 | 0.3606 | 0.0142 | 202 (0.202) | 0.08 |
| 28 | 0.0810 | 0.3211 | 0.0126 | 160 (0.160) | 0.08 |
| 29 | 0.0642 | 0.2859 | 0.0113 | 127 (0.127) | 0.05 |
| 30 | 0.0509 | 0.2546 | 0.0100 | 101 (0.101) | 0.05 |
| 31 | 0.0404 | 0.2268 | 0.0089 | 80 (0.080) | 0.05 |
| 32 | 0.0320 | 0.2019 | 0.0080 | 63 (0.063) | < 0.05 |
| 33 | 0.0254 | 0.1798 | 0.0071 | 50 (0.050) | < 0.05 |
| 34 | 0.0201 | 0.1601 | 0.0063 | 40 (0.040) | < 0.05 |
| 35 | 0.0160 | 0.1426 | 0.0056 | 32 (0.032) | < 0.05 |
| 36 | 0.0127 | 0.1270 | 0.0050 | 25 (0.025) | < 0.05 |
| 37 | 0.0100 | 0.1131 | 0.0045 | 20 (0.020) | < 0.05 |
| 38 | 0.0080 | 0.1007 | 0.0040 | 16 (0.016) | < 0.05 |
| 39 | 0.0063 | 0.0897 | 0.0035 | 12 (0.012) | < 0.05 |
| 40 | 0.0050 | 0.0799 | 0.0031 | 10 (0.010) | < 0.05 |
Sizes below 0.5 mm² (0.05 to 0.34 mm²) are common metric wire sizes below the IEC 60228 range. “< 0.05” means the wire is smaller than any listed metric size. Stranded conductors of the same AWG have a slightly larger overall diameter.
AWG follows the exact ASTM B258 formula: diameter (mm) = 0.127 × 92(36 − AWG) / 39. For a common hook-up wire size like 20 AWG:
20 AWG = 0.812 mm = 0.518 mm²
The cross-section follows from the diameter: area = π/4 × d² ≈ 0.518 mm², which is about 1,020 circular mils. The nearest IEC 60228 metric size is 0.5 mm².
American Wire Gauge (AWG) is a standard sizing system widely used in North America, with nominal dimensions for round solid conductors specified in ASTM B258. Sizes run in a geometric progression: a smaller gauge number means a larger wire, a decrease of 6 gauge numbers approximately doubles the diameter, and a decrease of 10 approximately multiplies the cross-section by ten. Larger than 0 AWG, the sizes continue as 00 (2/0), 000 (3/0), and 0000 (4/0), the largest standard AWG size; larger conductors are generally specified in kcmil. European designs usually specify conductors by nominal cross-section in mm², with IEC 60228 applying to many power cables and cords — which is why comparing the two sizing systems is a common step in cable design.
The values describe a bare solid conductor. Stranded wire of the same AWG has the same total copper cross-section but a slightly larger overall diameter — check the manufacturer datasheet for the finished OD.
Need to combine several wires into one equivalent size? Use the Combined Wire Gauge Calculator. Converting metric drawings to tape-measure fractions? Try the mm to Inches Fraction Calculator, or browse all our engineering tools.
