BS Fixings

Wire Gauge Chart

Wire gauge is a measurement of wire diameter. Understanding the differences in wire gauge sizes can often be confusing. The main difference between SWG and AWG is where the standards originated from. SWG is a British standard while AWG is an American standard.

SWG

British Standard Wire Gauge (SWG) is a set of wire sizes given by BS 3737:1964 (now withdrawn). You may also have heard this referred to as the Imperial Wire Gauge. As of 1884 in the UK the legal standard of measuring wire was SWG.

AWG

This is the standard in the United States for measuring the diameters of round, solid, nonferrous, electrically conducting wire. This is recorded in the imperial system of measurement. The gauge sizes are each 26% apart based on the cross sectional area. This standard is also known as 'Brown and Sharpe'. 

Wire Number (Gauge) Standard Wire Gauge (SWG) American Wire Gauge (AWG)
Gauge Inches Equivalent in mm Inches Equivalent in mm
10 0.128 3.251 0.1019 2.5883
11 0.116 2.946 0.0907 2.3038
12 0.104 2.642 0.0808 2.0523
13 0.092 2.337 0.072 1.8288
14 0.08 2.032 0.0641 1.6281
15 0.072 1.829 0.0571 1.4503
16 0.064 1.626 0.0508 1.2903
17 0.056 1.422 0.0453 1.1506
18 0.048 1.219 0.0403 1.0236
19 0.04 1.016 0.0359 0.9119
20 0.036 0.914 0.032 0.8128
21 0.032 0.813 0.0285 0.7239
22 0.028 0.711 0.0253 0.6426
23 0.024 0.61 0.0226 0.574
24 0.022 0.599 0.0201 0.5105
25 0.02 0.508 0.0179 0.4547
26 0.018 0.457 0.0159 0.4039
27 0.0164 0.417 0.0142 0.3607
28 0.0148 0.376 0.0126 0.32
29 0.0136 0.345 0.0113 0.287
30 0.0124 0.315 0.01 0.254
31 0.0116 0.295 0.0089 0.2261
32 0.0108 0.274 0.008 0.2032
33 0.01 0.254 0.0071 0.1803
34 0.0092 0.234 0.0063 0.16
35 0.0084 0.213 0.0056 0.1422
36 0.0076 0.193 0.005 0.127
37 0.0068 0.173 0.0045 0.1143
38 0.006 0.152 0.004 0.1016
39 0.0052 0.132 0.0035 0.0889
40 0.0048 0.122 0.0031 0.0787
41 0.0044 0.112 0.0028 0.0711
42 0.004 0.102 0.0025 0.0635
43 0.0036 0.0914 0.0022 0.0559
44 0.0032 0.0813 0.002 0.0508
45 0.0028 0.0711 0.0018 0.0457
46 0.0024 0.061 0.0016 0.0406
47 0.002 0.0508 0.0014 0.0356
48 0.0016 0.0406 0.0012 0.0305
49 0.0012 0.0305 0.0011 0.0279
50 0.001 0.0254 0.001 0.0254
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