# AWG wire gauge table (ASTM B258): 4/0 to 56 AWG, diameter in mils, inches and mm, area in circular mils and mm²

> What is the diameter of 12 AWG, 14 AWG or 10 AWG wire in inches and mm?

- Category: Electronics › Wiring & connectors
- Kind: Standard part
- Basis: ASTM B258 Table 1 (nominal diameters and cross-sectional areas of AWG solid round wires at 20 °C), all 60 rows as printed; numbers only
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**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- ASTM B258 Table 1: standard nominal diameters and cross-sectional areas of AWG sizes of solid round wire at 20 °C, 4/0 to 56 AWG, as printed in the iTeh sample of ASTM B258-02. One mil is 0.001 in. The inch column is the mil value divided by 1000 (the standard prints mils and mm); the other columns are as printed. Per the standard, 4/0 to 44 AWG diameters are given to no more than four significant figures and 0.1 mil, 45 to 56 AWG to 0.01 mil; diameters are calculated from the AWG law and rounded only at the end.
- Xem check: the printed mil values for 4/0 to 44 agree with the AWG law d = 0.005 in × 92^((36 − n) / 39) (n is the gauge number, with 1/0 = 0, 2/0 = -1, 3/0 = -2, 4/0 = -3) to within the standard's rounding, and every mm value but one (flagged below) equals mils × 0.0254 within its rounding. Each step down in gauge number is a factor of 92^(1/39) = 1.1229 in diameter; six gauges halve the diameter (about) and three gauges halve the area.
- One printed value is inconsistent: the sample's mm diameter for 19 AWG is 0.904, but its own 35.9 mils is 0.912 mm and its area 0.653 mm² is that of a 0.912 mm wire (a 0.904 mm wire would be 0.642 mm²). The printed number is kept and flagged in the table; use 0.912 mm unless you have the standard in hand. Those are the solid conductor sizes. A stranded conductor of the same AWG has a larger overall diameter (7 strands = three strand diameters across, 19 strands = five, 37 = seven, and so on) and the strand diameters are in the stranding standards, not in B258. Insulated outside diameters differ by insulation type and maker: no maker-published table that could be read is on this page. Sized tubes for wires are on the heat-shrink and cable-gland pages.
- A different series: SWG (British) and metric mm² sizes are on their own pages; sheet metal gauge numbers are not wire gauge numbers (the aluminium and brass sheet gauge uses the same AWG / Brown & Sharpe diameters, steel sheet gauge does not).
- The standard is sold by ASTM; the table here is the one in the sample the publisher gives out. No files: wire is a plain cylinder.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| solid wire of a given AWG | diameter per the table, 20 °C (12 AWG 2.05 mm, 14 AWG 1.63 mm, 18 AWG 1.02 mm) | a clamp terminal, ferrule or crimp barrel sized for that AWG (the terminal maker's table governs) | designed | all |

## Sizes

| AWG | diameter (mils) | diameter (in, mils ÷ 1000) | diameter (mm) | area (circular mils) | area (mm²) |
|---|---|---|---|---|---|
| 4/0 | 460.0 | 0.4600 | 11.684 | 211600 | 107.2 |
| 3/0 | 409.6 | 0.4096 | 10.404 | 167800 | 85.0 |
| 2/0 | 364.8 | 0.3648 | 9.26 | 133100 | 67.4 |
| 1/0 | 324.9 | 0.3249 | 8.25 | 105600 | 53.5 |
| 1 | 289.3 | 0.2893 | 7.35 | 83690 | 42.4 |
| 2 | 257.6 | 0.2576 | 6.54 | 66360 | 33.6 |
| 3 | 229.4 | 0.2294 | 5.82 | 52620 | 26.7 |
| 4 | 204.3 | 0.2043 | 5.19 | 41740 | 21.1 |
| 5 | 181.9 | 0.1819 | 4.62 | 33090 | 16.8 |
| 6 | 162.0 | 0.1620 | 4.11 | 26240 | 13.3 |
| 7 | 144.3 | 0.1443 | 3.67 | 20820 | 10.6 |
| 8 | 128.5 | 0.1285 | 3.26 | 16510 | 8.37 |
| 9 | 114.4 | 0.1144 | 2.91 | 13090 | 6.63 |
| 10 | 101.9 | 0.1019 | 2.59 | 10380 | 5.26 |
| 11 | 90.7 | 0.0907 | 2.30 | 8230 | 4.17 |
| 12 | 80.8 | 0.0808 | 2.05 | 6530 | 3.31 |
| 13 | 72.0 | 0.0720 | 1.83 | 5180 | 2.63 |
| 14 | 64.1 | 0.0641 | 1.63 | 4110 | 2.08 |
| 15 | 57.1 | 0.0571 | 1.45 | 3260 | 1.65 |
| 16 | 50.8 | 0.0508 | 1.29 | 2580 | 1.31 |
| 17 | 45.3 | 0.0453 | 1.15 | 2050 | 1.04 |
| 18 | 40.3 | 0.0403 | 1.02 | 1620 | 0.823 |
| 19 | 35.9 | 0.0359 | 0.904 (as printed; mils × 0.0254 = 0.912) | 1290 | 0.653 |
| 20 | 32.0 | 0.0320 | 0.813 | 1020 | 0.519 |
| 21 | 28.5 | 0.0285 | 0.724 | 812 | 0.412 |
| 22 | 25.3 | 0.0253 | 0.643 | 640 | 0.324 |
| 23 | 22.6 | 0.0226 | 0.574 | 511 | 0.259 |
| 24 | 20.1 | 0.0201 | 0.511 | 404 | 0.205 |
| 25 | 17.9 | 0.0179 | 0.455 | 320 | 0.162 |
| 26 | 15.9 | 0.0159 | 0.404 | 253 | 0.128 |
| 27 | 14.2 | 0.0142 | 0.361 | 202 | 0.102 |
| 28 | 12.6 | 0.0126 | 0.320 | 159 | 0.0804 |
| 29 | 11.3 | 0.0113 | 0.287 | 128 | 0.0647 |
| 30 | 10.0 | 0.0100 | 0.254 | 100 | 0.0507 |
| 31 | 8.9 | 0.0089 | 0.226 | 79.2 | 0.0401 |
| 32 | 8.0 | 0.0080 | 0.203 | 64.0 | 0.0324 |
| 33 | 7.1 | 0.0071 | 0.180 | 50.4 | 0.0255 |
| 34 | 6.3 | 0.0063 | 0.160 | 39.7 | 0.0201 |
| 35 | 5.6 | 0.0056 | 0.142 | 31.4 | 0.0159 |
| 36 | 5.0 | 0.0050 | 0.127 | 25.0 | 0.0127 |
| 37 | 4.5 | 0.0045 | 0.114 | 20.2 | 0.0103 |
| 38 | 4.0 | 0.0040 | 0.102 | 16.0 | 0.00811 |
| 39 | 3.5 | 0.0035 | 0.0890 | 12.2 | 0.00621 |
| 40 | 3.1 | 0.0031 | 0.0787 | 9.61 | 0.00487 |
| 41 | 2.8 | 0.00280 | 0.0711 | 7.84 | 0.00397 |
| 42 | 2.5 | 0.00250 | 0.0635 | 6.25 | 0.00317 |
| 43 | 2.2 | 0.00220 | 0.0559 | 4.84 | 0.00245 |
| 44 | 2.0 | 0.00200 | 0.0508 | 4.00 | 0.00203 |
| 45 | 1.76 | 0.00176 | 0.0447 | 3.10 | 0.00157 |
| 46 | 1.57 | 0.00157 | 0.0399 | 2.46 | 0.00125 |
| 47 | 1.40 | 0.00140 | 0.0356 | 1.96 | 0.000993 |
| 48 | 1.24 | 0.00124 | 0.0315 | 1.54 | 0.000779 |
| 49 | 1.11 | 0.00111 | 0.0282 | 1.23 | 0.000624 |
| 50 | 0.99 | 0.00099 | 0.0252 | 0.980 | 0.000497 |
| 51 | 0.88 | 0.00088 | 0.0224 | 0.774 | 0.000392 |
| 52 | 0.78 | 0.00078 | 0.0198 | 0.608 | 0.000308 |
| 53 | 0.70 | 0.00070 | 0.0178 | 0.490 | 0.000248 |
| 54 | 0.62 | 0.00062 | 0.0158 | 0.384 | 0.000195 |
| 55 | 0.55 | 0.00055 | 0.0140 | 0.302 | 0.000153 |
| 56 | 0.49 | 0.00049 | 0.0125 | 0.240 | 0.000122 |

## Where the files are

- ASTM (iTeh sample copy): [ASTM B258-02: Table 1, standard nominal diameters and cross-sectional areas of AWG sizes of solid round wires at 20 C, 4/0 to 56](https://cdn.standards.iteh.ai/samples/959/0248539ea2744b1b909bfde58d575ab1/ASTM-B258-02.pdf) — web — Publisher's page; dimensions are facts
- ASTM: [ASTM B258 Standard Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors](https://webstore.ansi.org/standards/astm/astmb25802) — web — Standards body's page; dimensions are facts

## Questions

**What is the diameter of 12 AWG wire?**

0.0808 in (80.8 mils, 2.05 mm), area 6530 circular mils or 3.31 mm² for solid wire (ASTM B258).

**What is the diameter of 14 AWG wire?**

0.0641 in (1.63 mm), 2.08 mm² for solid wire.

**How big is 10 AWG in mm?**

2.59 mm diameter, 5.26 mm² area, solid.

**What is 4/0 AWG in mm?**

11.684 mm (0.4600 in), 107.2 mm² area, solid.

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