Common Wire Gauges

The common U.S. wire gauges (called AWG gauges) refer to sizes of copper wire. The resistivity of copper at 20 C is about

This table uses this value of resistivity, but it is known to vary by a few percent based on purity and process of manufacture.

AWG wire
size (solid)
Diameter
(inches)
Resistance per
1000 ft (ohms)
Resistance per
1000 m (ohms)
24
0.0201
25.67
84.2
22
0.0254
16.14
52.7
20
0.0320
10.15
33.2
18
0.0403
6.385
20.9
16
0.0508
4.016
13.2
14
0.0640
2.525
8.28
12
0.0808
1.588
5.21
10
0.1019
0.999
3.28
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American Wire Gages (AWG) Sizes and Resistances

AWG wire
size (solid)
Area
CM*
Resistance per
1000 ft (ohms) @ 20 C
Diameter
(inches)
Maximum current**
(amperes)
0000
211600
0.049
0.46
380
000
167810
0.0618
0.40965
328
00
133080
0.078
0.3648
283
0
105530
0.0983
0.32485
245
1
83694
0.124
0.2893
211
2
66373
0.1563
0.25763
181
3
52634
0.197
0.22942
158
4
41742
0.2485
0.20431
135
5
33102
0.3133
0.18194
118
6
26250
0.3951
0.16202
101
7
20816
0.4982
0.14428
89
8
16509
0.6282
0.12849
73
9
13094
0.7921
0.11443
64
10
10381
0.9989
0.10189
55
11
8234
1.26
0.09074
47
12
6529
1.588
0.0808
41
13
5178.4
2.003
0.07196
35
14
4106.8
2.525
0.06408
32
15
3256.7
3.184
0.05707
28
16
2582.9
4.016
0.05082
22
17
2048.2
5.064
0.04526
19
18
1624.3
6.385
0.0403
16
19
1288.1
8.051
0.03589
14
20
1021.5
10.15
0.03196
11
21
810.1
12.8
0.02846
9
22
642.4
16.14
0.02535
7
23
509.45
20.36
0.02257
4.7
24
404.01
25.67
0.0201
3.5
25
320.4
32.37
0.0179
2.7
26
254.1
40.81
0.01594
2.2
27
201.5
51.47
0.0142
1.7
28
159.79
64.9
0.01264
1.4
29
126.72
81.83
0.01126
1.2
30
100.5
103.2
0.01002
0.86
31
79.7
130.1
0.00893
0.7
32
63.21
164.1
0.00795
0.53
33
50.13
206.9
0.00708
0.43
34
39.75
260.9
0.0063
0.33
35
31.52
329
0.00561
0.27
36
25
414.8
0.005
0.21
37
19.83
523.1
0.00445
0.17
38
15.72
659.6
0.00396
0.13
39
12.47
831.8
0.00353
0.11
40
9.89
1049
0.00314
0.09

The U.S. wire gauges (called AWG gauges) refer to sizes of copper wire. This table corresponds to a resistivity of

for copper at 20 C. This table uses this value of resistivity, but it is known to vary by a few percent based on purity and process of manufacture.

*The AWG system states areas of round copper wires in "circular mils", which is the square of the diameter in mils. 1 mil =.001 inch.

This data from Floyd, Electric Circuit Fundamentals, 2nd Ed.

**Maximum current for chassis wiring. Data from Handbook of Electronic Tables and Formulas for American Wire Gauge. The maximum current for power transmission is less.

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Reference
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