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Wire Gauges & Comparision Table.
By Brian, MW0GKX.

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Wire gauge is a measurement of how large a wire is, either in diameter or cross sectional area. This determines the amount of electrical current a wire can safely carry, as well as its electrical resistance and weight per unit of length. Wire gauge is applicable to both electrical and non-electrical wires.

In some applications wire sizes are specified as the cross sectional area of the wire, usually in mm². Advantages of this system include the ability to readily calculate the physical dimensions or weight of wire, ability to take account of non-circular wire, and ease of calculation of electrical properties.

There seem to be as many Wire Gauges as there are stars in the sky! Here I will deal with the most common: AWG and SWG along with the up and coming Metric.

American wire gauge (AWG).

Also known as the "Brown and Sharpe" wire gauge, is used in the United States since at least the 1880s as a standard method of denoting wire diameter for nonferrous, electrically conducting wire. Also used in other countries.

Increasing numbers give decreasing wire diameters, which is similar to many other non-metric gauging systems. This seemingly counterintuitive numbering is derived from the fact that the gauge number is related to the number of drawing operations that must be used to produce a given gauge of wire; very fine wire (for example, 30 gauge) requires far more passes through the drawing dies than does 0 gauge wire.

Number 0000 (4/0) wire is 0.4600 inch (11.68 mm) in diameter. The diameter of each succeeding size is 0.890525 times the diameter of the previous size.

British Standard / British Standard Gauge / Imperial Wire Gauge / Imperial Standard Wire Gauge / Standard Wire Gauge (SWG).

Sanctioned by the British Board of Trade, British Standard Gauge was formulated by J. Latimer Clark. Fixed by order of council August 23, 1883, it was made by improving on the Birmingham wire gauge. Made legal standard on March 1, 1884.

It differs from the then pre-existing gauges scarcely more than they differ among themselves. It is based on a rational system, the basis being the mil. No. 7/0 (0000000), the largest size, is 0.50 in. (500 mils or 12.7 mm) in diameter, and the smallest, No. 50, is 0.001 in. (1 mil or about 25 µm) in diameter. Between these the diameter, or thickness, diminishes by 10.557%, and the weight diminishes by 20%.

Metric Gauge.

In the Metric Gauge scale, the gauge is 10 times the diameter in millimeters, so a 50 gauge metric wire would be 5 mm in diameter. Note that in AWG and SWG the diameter goes up as the gauge goes down, but for metric gauges it is the opposite. Probably because of this confusion metric sized wire is usually specified in millimeters rather than metric gauges. Metric gauge sizes can also be decimal fractioned, i.e: 12.5 Metric Gauge is one and a quater mm.

Just to confuse the issue even more wire and cable are often quoted as mm² so I have included the mm² values as well.

Generally available mm² sizes are:
1mm², 1.5mm², 2.5mm², 4mm², 6mm²,10mm², 16mm², 25mm², 35mm², 50mm², 70mm², 95mm² and 120mm².

Wire Gauge Sizes Comparison Table.

This table does not give current capacity because the current handling of any wire depends on the gauge, insulation, temperature, bundling, etc.

What I have done is to place the wires in order from the largest (top) to smallest (bottom) with their measurements in inch and metric, the measurements are colour coded to make it easier to follow with headings repeated for easy viewing. The dimensions refer to solid, single core wire.

Not all Metric Gauge sizes are included as they are easy to work out.

Obviously if you are making a project and a certain gauge is specified but not to hand use the next larger that you have available.

If you spot any errors feel free to let me know, the information came from several sources and, as is usual in cases like this, some of it disagreed!

AWG SWG Metric gauge mm² Diameter Inch Diameter mm
= (7/0)
0000000
127 = 0.50 12.7
= = 125 = 0.4331 12.54
= = 120 = 0.4331 12
= (6/0)
000000
= = 0.464 11.7856
(4/0)
0000
= = 107.22 0.46 11.684
= = 115 = 0.4527 11.5
= = 110 = 0.4331 11
= (5/0)
00000
= = 0.432 10.9728
= = 105 = 0.4134 10.5
(3/0)
000
= = 85.01 0.4096 10.4038
AWGSWGMetric gaugemm²Diameter InchDiameter mm
= (4/0)
0000
= = 0.400 10.16
= = 100 = 0.3937 10
= = 95 = 0.374 9.5
= (3/0)
000
= = 0.372 9.4488
(2/0)
00
= = 67.43 0.3648 9.2659
= = 90 = 0.3543 9
= (2/0)
00
= = 0.348 8.8392
= = 85 = 0.3346 8.5
0 = = 53.49 0.3249 8.2525
= 0 = = 0.324 8.2296
= = 80 = 0.315 8
AWGSWGMetric gaugemm²Diameter InchDiameter mm
= 1 = = 0.3 7.62
= = 75 = 0.2963 7.5
1 = = 42.41 0.2893 7.3482
= 2 = = 0.276 7.0104
= = 70 = 0.2756 7
2 = = 33.62 0.2576 6.543
= = 65 = 0.2559 6.5
= 3 = = 0.252 6.4008
= = 60 = 0.2362 6
= 4 = = 0.232 5.8928
3 = = = 0.2294 5.8268
= = 55 = 0.2165 5.5
= 5 = = 0.212 5.3848
4 = = 21.15 0.2043 5.1892
AWGSWGMetric gaugemm²Diameter InchDiameter mm
= = 50 = 0.1968 5
= 6 = = 0.192 4.8768
5 = = = 0.1819 4.6203
= = 45 = 0.1772 4.5
= 7 = = 0.176 4.4704
6 = = 13.3 0.162 4.1148
= 8 = = 0.16 4.064
= = 40 = 0.1575 4
7 = = = 0.1443 3.6652
= 9 = = 0.144 3.6576
= = 35 = 0.1378 3.5
8 = = 8.3 0.1285 3.2639
= 10 = = 0.128 3.2512
= = 30 = 0.1181 3
AWGSWGMetric gaugemm²Diameter InchDiameter mm
= 11 = = 0.116 2.9464
9 = = = 0.1144 2.9058
= 12 = = 0.104 2.6416
10 = = 5.26 0.1019 2.5883
= = 25 4.91 0.0984 2.5
= 13 = = 0.092 2.3368
11 = = = 0.0907 2.3038
12 = = 3.3 0.0808 2.0523
= 14 = = 0.08 2.032
= = 20 3.14 0.0787 2
13 15 = 2.6 0.072 1.8288
14 = = 2 0.0641 1.6281
= 16 = = 0.064 1.6256
= = 15 = 0.059 1.5
AWGSWGMetric gaugemm²Diameter InchDiameter mm
15 = = = 0.0571 1.4503
= 17 = = 0.056 1.4224
16 = = 1.3 0.0508 1.2903
= 18 = = 0.048 1.2192
17 = = = 0.0453 1.1506
18 = = 0.82 0.0403 1.0236
= 19 10 0.8 0.04 1
= 20 = = 0.036 0.9144
19 = = = 0.0359 0.9119
= = 9 = 0.354 0.9
20 21 = 0.5 0.032 0.8128
= = 8 0.5 0.0315 0.8
21 = = = 0.0285 0.7239
= 22 = = 0.028 0.7112
AWGSWGMetric gaugemm²Diameter InchDiameter mm
= = 7 = 0.0275 0.7
22 = = 0.33 0.0254 0.6452
= 23 = = 0.024 0.6096
= = 6 0.28 0.0236 0.6
23 = = = 0.0226 0.5740
= 24 = = 0.022 0.5588
24 = = = 0.0201 0.5105
= 25 = = 0.02 0.508
= = 5 0.2 0.0197 0.5
= 26 = = 0.018 0.4572
25 = = 0.16 0.0179 0.4547
= 27 = = 0.0164 0.4166
26 = = 0.13 0.0159 0.4039
= = 4 = 0.0157 0.4
= 28 = = 0.0148 0.3759
AWGSWGMetric gaugemm²Diameter InchDiameter mm
27 = = 0.096 0.0142 0.3607
= 29 = = 0.0136 0.3544
28 = = 0.08 0.0126 0.32
= 30 = = 0.0124 0.315
= = 3 = 0.0118 0.3
= 31 = = 0.0116 0.2946
29 = = = 0.0113 0.287
= 32 = = 0.0108 0.2743
30 33 = 0.049 0.01 0.254
= 34 = = 0.0092 0.2337
31 = = = 0.0089 0.2261
= 35 = = 0.0084 0.2134
32 = = 0.031 0.008 0.2032
= = 2 = 0.0079 0.2
AWGSWGMetric gaugemm²Diameter InchDiameter mm
= 36 = = 0.0076 0.193
33 = = 0.026 0.0071 0.1803
= 37 = = 0.0068 0.1727
34 = = 0.02 0.0063 0.16
= 38 = = 0.006 0.1524
35 = = 0.015 0.0056 0.1422
= 39 = = 0.0052 0.1321
36 = = 0.013 0.005 0.127
= 40 = = 0.0048 0.1219
37 = = 0.0095 0.0045 0.1143
= 41 = = 0.0044 0.1118
38 42 = 0.0078 0.004 0.1016
= = 1 = 0.0039 0.1
= 43 = = 0.0036 0.0914
AWGSWGMetric gaugemm²Diameter InchDiameter mm
39 = = 0.0064 0.0035 0.0889
= 44 = = 0.0032 0.0813
40 = = 0.0050 0.0031 0.0787
41 45 = 0.0039 0.0028 0.0711
42 = = 0.0028 0.0025 0.0635
= 46 = = 0.0024 0.0610
43 = = = 0.0022 0.0559
44 47 = 0.002 0.002 0.0508
45 = = = 0.00176 0.0447
= 48 = = 0.0016 0.0496
46 = = 0.0013 0.00157 0.0399
47 = = = 0.0014 0.0356
48 49 = = 0.0012 0.0305
AWGSWGMetric gaugemm²Diameter InchDiameter mm
49 = = = 0.0011 0.0279
= 50 = = 0.001 0.0254
50 = = = 0.00099 0.025146

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