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SWG to mm conversion and calculator

Standard wire gauge (SWG) to mm and mm2 converison calculator, chart and how to convert.

SWG to mm conversion calculator



Select gauge #:  
 
 
 
Diameter in millimeters: mm
 
Diameter in inches: in
Cross sectional area in square millimeters: mm2



Wire cross sectional area calculation and Chart

The n gauge wire's cross sercional area An in square millimeters (mm2) is equal to pi divided by 4 times the square wire diameter d in millimeters (mm):

An (mm2) = (π/4)×dn2


What is SWG

British Standard Wire Gauge is a unit for denoting wire size given by BS 3737:1964. It is also known as the Imperial Wire Gauge or British Standard Gauge. Use of SWG sizes has fallen greatly in popularity, but is still used as a measure of thickness in guitar strings and some electrical wire.

SWG to mm conversion chart

SWG # Diameter
(mm)
Area
(mm2)
7/0 12.700 126.6769
6/0 11.786 109.0921
5/0 10.973 94.5638
4/0 10.160 81.0732
3/0 9.449 70.1202
2/0 8.839 61.3643
0 8.230 53.1921
1 7.620 45.6037
2 7.010 38.5989
3 6.401 32.1780
4 5.893 27.2730
5 5.385 22.7735
6 4.877 18.6793
7 4.470 15.6958
8 4.064 12.9717
9 3.658 10.5071
10 3.251 8.3019
11 2.946 6.8183
12 2.642 5.4805
13 2.337 4.2888
14 2.032 3.2429
15 1.829 2.6268
16 1.626 2.0755
17 1.422 1.5890
18 1.219 1.1675
19 1.016 0.8107
20 0.914 0.6567
21 0.813 0.5189
22 0.711 0.3973
23 0.610 0.2919
24 0.559 0.2452
25 0.5080 0.2027
26 0.4572 0.1642
27 0.4166 0.1363
28 0.3759 0.1110
29 0.3454 0.0937
30 0.3150 0.0779
31 0.2946 0.0682
32 0.2743 0.0591
33 0.2540 0.0507
34 0.2337 0.0429
35 0.2134 0.0358
36 0.1930 0.0293
37 0.1727 0.0234
38 0.1524 0.0182
39 0.1321 0.0137
40 0.1219 0.0117
41 0.1118 0.0098
42 0.1016 0.0081
43 0.0914 0.0066
44 0.0813 0.0052
45 0.0711 0.0040
46 0.0610 0.0029
47 0.0508 0.0020
48 0.0406 0.0013
49 0.0305 0.0007
50 0.0254 0.0005