AWG wire gauge table (ASTM B258): 4/0 to 56 AWG, diameter in mils, inches and mm, area in circular mils and mm² — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/awg-wire-gauge-table-astm-b258/ (sheet CC BY 4.0) 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 Catalog version: 2026-10-20 Sizes: see table below - 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. 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 Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - 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 — web — Publisher's page; dimensions are facts — https://cdn.standards.iteh.ai/samples/959/0248539ea2744b1b909bfde58d575ab1/ASTM-B258-02.pdf - ASTM: ASTM B258 Standard Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors — web — Standards body's page; dimensions are facts — https://webstore.ansi.org/standards/astm/astmb25802 No true-size file yet: the published figures do not fix the whole shape; a measured scan is planned. API: https://xemstudio.com/api/geometry?object=awg-wire-gauge-table-astm-b258