Copper Wire Properties & Gauge Conversions

Values presented here are standards available for many independent publications, but ultimately they all originate from the American Wire Gauge (AWG) system (also aka the Brown and Sharp gauge). It has been in existence since the mid 1800s in the U.S. and Canada.

Note that as wire gauge number is increased the wire diameter decreases. Although it might seem somewhat backward, there is a good reason for it. Originally, it was related to the number of time a wire needed to be drawn through an extraction die in order to achieve the final wire size.

By definition, 36 AWG is 0.0050 inches in diameter, and 0000 is 0.4600 inches in diameter. The ratio of these diameters is 92, and there are 40 gauge sizes from #36 to #0000, or 39 steps. Using this ratio, wire gauge sizes vary geometrically according to the following formula: The diameter of an n AWG wire is:

AWG wire diameter equation for solid wire - RF Cafe

Accordingly, the ASTM B 258-02 standard defines the ratio between successive sizes to be the 39th root of 92, or approximately 1.1229322.

AWG wire gauge equation for solid wire - RF Cafe

Stranding designation of a/b means a number of b gauge wires. E.g., 7/44 means 7 strands of 44 AWG solid wire.

Note: Just a 3 dB change in power represents a doubling (or halving) of power, a change of 3 wire sizes represents approximately a doubling (or halving) of cross-sectional area.

See wire gauge conversion chart at bottom of page.  Values given at 25 °C.

AWG Stranding Approx. 0.D. Circular
Mil
Area 		Weight
(lbs/1000 ft) 		Weight
(kg/km) 		Resistance
(Ω/1000 ft)		 Resistance
(Ω/km)
Inches mm
40 Solid 0.003145 0.07988 9.888 0.02993      
39 Solid 0.003531 0.08969 12.47 0.03774      
38 Solid 0.003965 0.1007 15.72 0.04759      
37 Solid 0.004453  0.1131 19.83 0.06001      
36 Solid 0.005000 0.1270 25.00 0.07568 0.113 445.0 1460.0
36 7/44 0.0060 0.152 28.0 0.085 0.126 371.0 1271.0
35 Solid 0.005614   31.52 0.09542      
34 Solid 0.006304 0.1601 39.75 0.1203 0.179 280.0 9180.0
34 7/42 0.0075 0.192 43.8 0.132 0.196 237.0 777.0
33 Solid 0.007080 0.1798 50.13 0.1517      
32 Solid 0.007950 0.2019 63.21 0.1913 0.289 174.0 571.0
32 7/40 0.008 0.203 67.3 0.203 0.302 164.0 538.0
32 19/44 0.009 0.229 76.0 0.230 0.342 136.0 448.0
31 Solid 0.007950 0.2268 79.70 0.2413      
30 Solid 0.01003 0.2548 100.5 0.3042 0.45 113.0 365.0
30 7/38 0.012 0.305 112.0 0.339 0.504 103.0 339.0
30 19/42 0.012 0.305 118.0 0.359 0.534 87.3 286.7
29 Solid 0.01126 0.2860 126.7 0.3836      
28 Solid 0.01246 0.3211 159.8 0.4837 0.72 70.8 232.0
28 7/36 0.015 0.381 175.0 0.529 0.787 64.9 213.0
28 19/40 0.016 0.406 182.6 0.553 0.823 56.7 186.0
27 Solid 0.01419 0.3604 201.5 0.6100      
27 7/35 0.018 0.457 219.1 0.664 0.988 54.5 179.0
26 Solid 0.01594 0.4049 254.1 0.7692 1.14 43.6 143.0
26 10/36 0.021 0.533 250.0 0.757 1.13 41.5 137.0
26 19/38 0.020 0.508 304.0 0.920 1.37 34.4 113.0
26 7/34 0.019 0.483 277.1 0.841 1.25 37.3 122.0
25 Solid 0.01790 0.4547 320.4 0.9699      
24 Solid 0.02010 0.5105 404.0 1.223 1.82 27.3 89.4
24 7/32 0.024 0.610 448.0 1.36 2.02 23.3 76.4
24 10/34 0.023 0.582 396.1 1.20 1.79 26.1 85.6
24 19/36 0.024 0.610 475.0 1.43 2.13 21.1 69.2
24 41/40 0.023 0.582 384.4 1.16 1.73 25.6 84.0
23 Solid 0.02257 0.5733 509.5 1.542      
22 Solid 0.02535 0.6439 642.4 1.945 2.91 16.8 55.3
22 7/30 0.030 0.762 700.0 2.12 3.16 14.7 48.4
22 19/34 0.031 0.787 754.1 2.28 3.39 13.7 45.1
22 26/36 0.030 0.762 650.0 1.97 2.93 15.9 52.3
21 Solid 0.02846 0.7229 810.1 2.452      
20 Solid 0.03196 0.8118 1022 3.092 4.61 10.5 34.6
20 7/28 0.038 0.965 1111 3.49 5.19 10.3 33.8
20 10/30 0.035 0.889 1000 3.03 4.05 10.3 33.9
20 19/32 0.037 0.940 1216 3.70 5.48 8.6 28.3
20 26/34 0.036 0.914 1031 3.12 4.64 10.0 33.0
20 41/36 0.036 0.914 1025 3.10 4.61 10.0 32.9
19 Solid 0.03589 0.9116 1288 3.899      
18 Solid 0.0403 1.024 1624 4.917 7.32 6.6 21.8
18 7/26 0.048 1.219 1769 5.36 7.98 5.9 19.2
18 16/30 0.047 1.194 1600 4.84 7.20 8.5 21.3
18 19/30 0.049 1.245 1900 5.75 8.56 5.5 17.9
18 41/34 0.047 1.194 1627 4.92 7.32 6.4 20.9
18 65/36 0.047 1.194 1625 4.91 7.31 6.4 21.0
17 Solid 0.04526 1.150 2048 6.200      
16 Solid 0.05082 1.291 2583 7.818 11.60 4.2 13.7
16 7/24 0.060 1.524 2828 8.56 12.74 3.7 12.0
16 65/34 0.059 1.499 2579 7.81 11.62 4.0 13.2
16 26/30 0.059 1.499 2600 7.87 11.71 4.0 13.1
16 19/29 0.058 1.473 2426 7.35 10.94 4.3 14.0
16 105/36 0.059 1.499 2625 7.95 11.83 4.0 13.1
15 Solid 0.05707 1.450 3257 12.43      
14 Solid 0.06408 1.628 4107 12.43 18.50 2.6 8.6
14 7/22 0.073 1.854 4480 13.56 20.18 2.3 7.6
14 19/27 0.073 1.854 3830 11.59 17.25 2.7 8.9
14 41/30 0.073 1.854 4100 12.40 18.45 2.5 8.3
14 105/34 0.073 1.854 4167 12.61 18.77 2.5 8.2
13 Solid 0.07196 1.828 5178 15.68      
12 Solid 0.08081 2.053 6530 19.77      
11 Solid 0.09074 2.305 8234 24.92      
10 Solid 0.1019 2.588 10380 31.43      
9 Solid 0.1144 2.906 13090 39.63      
8 Solid 0.1285 3.264 16510 49.98      
7 Solid 0.1443 3.665 20820 63.02      
6 Solid 0.1620 4.115 26250 79.46      
5 Solid 0.1819 4.620 33100 100.2      
4 Solid 0.2043 5.189 41740 126.4      
3 Solid 0.2294 5.827 52640 159.3      
2 Solid 0.2576 6.543 66370 200.9      
1 Solid 0.2893 7.348 83690 253.3      
0 Solid 0.3249 8.252 105500 319.5      
00 Solid 0.3648 9.266 133100 402.8      
000 Solid 0.4096 10.40 167800 507.9      
0000 Solid 0.4600 11.68 211600 640.5      

Wire Gauge Conversions

All Units Are in Inches

GAUGE # AWG W & M SWG BWG U.S. Standard
7/0 0.6513 0.490 0.500   0.5000
6/0 0.5800 0.460 0.464   0.4688
5/0 0.5165 0.430 0.432   0.4375
4/0 0.4600 0.3938 0.400 0.454 0.4063
3/0 0.4096 0.3625 0.372 0.425 0.3750
2/0 0.3648 0.3310 0.348 0.380 0.3438
1/0 0.3249 0.3065 0.324 0.340 0.3125
1 0.2893 0.2830 0.300 0.300 0.2813
2 0.2576 0.2625 0.276 0.284 0.2656
3 0.2294 0.2437 0.252 0.259 0.2391
4 0.2043 0.2253 0.232 0.238 0.2242
5 0.1819 0.2070 0.212 0.220 0.2092
6 0.1620 0.1920 0.192 0.203 0.1943
7 0.1443 0.1770 0.176 0.180 0.1793
8 0.1285 0.1620 0.160 0.165 0.1644
9 0.1144 0.1483 0.144 0.148 0.1495
10 0.1019 0.1350 0.128 0.134 0.1345
11 0.0907 0.1205 0.116 0.120 0.1196
12 0.0808 0.1055 0.104 0.109 0.1046
13 0.0719 0.0915 0.092 0.095 0.0897
14 0.0641 0.0800 0.080 0.083 0.0747
15 0.0571 0.0720 0.072 0.072 0.0673
16 0.0508 0.0625 0.064 0.065 0.0598
17 0.04526 0.054 0.056 0.058 0.0538
18 0.04030 0.0475 0.048 0.049 0.0478
19 0.03589 0.0410 0.040 0.042 0.0418
20 0.03196 0.0348 0.036 0.035 0.0359
21 0.02846 0.03175 0.032 0.032 0.0329
22 0.02535 0.0286 0.028 0.028 0.0299
23 0.02257 0.0258 0.024 0.025 0.0269
24 0.02010 0.0230 0.022 0.022 0.0239
25 0.01790 0.0204 0.020 0.020 0.0209
26 0.01594 0.0181 0.018 0.018 0.0179
27 0.01420 0.0173 0.0164 0.016 0.0164
28 0.01264 0.0162 0.0148 0.014 0.0149
29 0.01126 0.0150 0.0136 0.013 0.0135
30 0.0103 0.014 0.0124 0.012 0.0120
31 0.00893 0.0132 0.0116 0.010 0.0109
32 0.00795 0.0128 0.0108 0.009 0.0102
33 0.00708 0.0118 0.0100 0.008 0.0094
34 0.00630 0.0104 0.0092 0.007 0.0086
35 0.00561 0.0095 0.0084 0.005 0.0078
36 0.00500 0.0090 0.0076 0.004 0.0070
37 0.00445 0.0085 0.0068    
38 0.00396 0.0080 0.0060    
39 0.00353 0.0075 0.0052    
40 0.00314 0.007 0.0048    
41 0.00279 0.0066 0.0044    
42 0.00249 0.0062 0.0040    
43 0.00221 0.0060 0.0036    
44 0.00198 0.0058 0.0032    
45 0.00176 0.0055 0.0028    
46 0.00157 0.0052 0.0024    
47 0.00140 0.0050 0.0016    
48 0.00124 0.0048 0.0012    
49 0.00111 0.0046 0.0010    
50 0.00099 0.0044      
51 0.00088        
52 0.00078        
53 0.00070        
54 0.00060        
55 0.00050        
56 0.00040        
  • AWG = American Wire Gauge (Brown & Sharpe)
  • W & M = Washburn & Moen (steel wire gauge)
  • SWG = Imperial Standard Wire Gauge
  • BWG = Birmingham or Stubs Wire Gauge
  • US Standard = United States Standard (Revised)