AWG – American Wire Gauge

Wire sizes and strand sizes (for non-ferrous metals) can be indicated in two ways on the international level:
in mm or as AWG.

While the actual diameter is used within the metric system, the so-called AWG system represents a codification based on the number of manufacturing steps required.

AWG Diameter
in		 Diameter
mm		 Cross-section
cma		 Cross-section
mm²
0000 (4/0) 0.4600 11.6840 0.211600 107.2193
000 (3/0) 0.4096 10.4049 0.167772 85.0287
00 (2/0) 0.3648 9.2658 0.133079 67.4304
0 (1/0) 0.3249 8.2515 0.105560 53.4756
1 0.2893 7.3481 0.083694 42.4072
2 0.2576 6.5437 0.066358 33.6308
3 0.2294 5.8273 0.052624 26.6701
4 0.2043 5.1894 0.041738 21.1507
5 0.1819 4.6213 0.033088 16.7733
6 0.1620 4.1154 0.026244 13.3019
7 0.1443 3.6649 0.020822 10.5491
8 0.1285 3.2636 0.016512 8.3653
9 0.1144 2.9064 0.013087 6.6344
10 0.1019 2.5882 0.010384 5.2612
11 0.0907 2.3048 0.008226 4.1721
12 0.0808 2.0525 0.006529 3.3087
13 0.0720 1.8278 0.005184 2.6239
14 0.0641 1.6277 0.004109 2.0808
15 0.0571 1.4495 0.003260 1.6502
16 0.0508 1.2908 0.002581 1.3086
17 0.0453 1.1495 0.002052 1.0378
18 0.0403 1.0237 0.001624 0.8231
19 0.0359 0.9116 0.001289 0.6527
20 0.0320 0.8118 0.001024 0.5176
21 0.0285 0.7229 0.000812 0.4104
22 0.0253 0.6438 0.000640 0.3255
23 0.0226 0.5733 0.000511 0.2581
24 0.0201 0.5106 0.000404 0.2048
25 0.0179 0.4547 0.000320 0.1624
26 0.0159 0.4049 0.000253 0.1288
27 0.0142 0.3606 0.000202 0.1021
28 0.0126 0.3211 0.000159 0.0810
29 0.0113 0.2859 0.000128 0.0642
30 0.0100 0.2546 0.000100 0.0509
31 0.0089 0.2268 0.000079 0.0404
32 0.0080 0.2019 0.000064 0.0320
33 0.0071 0.1798 0.000050 0.0254
34 0.0063 0.1601 0.000040 0.0201
35 0.0056 0.1426 0.000031 0.0160
36 0.0050 0.1270 0.000025 0.0127
37 0.0045 0.1131 0.000020 0.0100
38 0.0040 0.1007 0.000016 0.0080
39 0.0035 0.0897 0.000012 0.0063
40 0.0031 0.0799 0.000010 0.0050

Strand
AWG		 Cross-section
mm²		 Number
of
wires		 Single
wires
AWG		 Single
wires
diameter
mm		 Conductor
diameter
nom.
mm		 Cross-section
CMA		 Single
wires
diameter
in		 Conductor
diameter
nom.
in
42/7 0.0034 7 50 0.025 0.075 6.86 0.0010 0.0030
40/7 0.0053 7 48 0.031 0.093 10.8 0.0012 0.0037
38/7 0.0088 7 46 0.040 0.120 17.4 0.0016 0.0047
36/7 0.0142 7 44 0.051 0.152 28.0 0.0020 0.0060
34/7 0.0222 7 42 0.064 0.191 43.8 0.0025 0.0075
32/7 0.0340 7 40 0.079 0.237 67.0 0.0031 0.0093
30/7 0.0570 7 38 0.102 0.306 112 0.0040 0.0120
28/7 0.0890 7 36 0.127 0.381 175 0.0050 0.0150
26/7 0.1400 7 34 0.160 0.480 278 0.0063 0.0189
24/7 0.2300 7 32 0.203 0.609 448 0.0080 0.0240
22/7 0.3500 7 30 0.254 0.762 700 0.0100 0.0300
20/7 0.5600 7 28 0.320 0.960 1111 0.0126 0.0378
18/7 0.9000 7 26 0.404 1.212 1770 0.0159 0.0477
32/19 0.0385 19 44 0.051 0.254 76.0 0.0020 0.0100
30/19 0.0602 19 42 0.064 0.318 119 0.0025 0.0125
28/19 0.0930 19 40 0.079 0.395 183 0.0031 0.0156
26/19 0.1500 19 38 0.102 0.510 304 0.0040 0.0201
24/19 0.2400 19 36 0.127 0.635 475 0.0050 0.0250
22/19 0.3800 19 34 0.160 0.800 754 0.0063 0.0315
20/19 0.6200 19 32 0.203 1.015 1216 0.0080 0.0400
18/19 0.9600 19 30 0.254 1.270 1900 0.0100 0.0500
16/19 1.2000 19 29 0.287 1.435 2426 0.0113 0.0565
14/19 1.9000 19 27 0.361 1.805 3831 0.0142 0.0711
12/19 3.1000 19 25 0.455 2.275 6088 0.0179 0.0896
14/37 1.8748 37 30 0.254 1.778 3700 0.0100 0.0700
12/37 3.0000 37 28 0.320 2.240 5874 0.0126 0.0882
10/37 4.7000 37 26 0.404 2.828 9354 0.0159 0.0113

AWG is an acronym for “American Wire Gauge” (German translation: “Amerikanische Drahtlehre”). As you may have already concluded, this coding system originates from North America. It reflects a geometric sequence that was introduced in the middle of the 19th century by Joseph Rogers Brown for use in his tool-making company Brown Sharpe.
The AWG standardized wire gauge system is used to plot diameters and cross-sections of electrical conductors made out of non-ferrous metals, applied to both wires and strands. The AWG graduation is based on the number of drawing steps required to produce a certain diameter. In order for the wire to arrive at the desired diameter, a fairly thick base wire (e.g. 0.8 mm) is drawn through the tapered mouth of a drawing die. Reducing the diameter only works very gradually, i.e. by means of several drawing steps, with the mouths that are used getting smaller and smaller until the final diameter is obtained.

The AWG system clearly defines the range 0000 (4/0) to 36, where all sizes in between adhere to a geometric sequence that comply with the following rule: the AWG figure is a function of the number of drawing steps resulting in ever-decreasing diameters. Even sizes below AWG36 follow the same pattern as they are derived from the size range initially covered. The unit of the diameter is in bzw. mils = in * 1.000 Cross-sections above 4/0 are indicated in cmils

Single-wire cross-section (d)

The ratio of the diameter of successive AWG sizes is specified in ASTM B 258-02:
This results in the following formula for calculating the wire diameter from the AWG number:
Calculation of the AWG number from the wire diameter:

Single wire cross-section

As opposed to the usual way of calculating a circular area (single-wire cross-section in mm) according to the formula
the AWG system features a simplified calculation using d².

This leads to an AWG cross-section stated in
“circular mil area” cma = (d mils)2.

Example:

AWG36 = 0,005 in = 5 mils

(5 mils)² = 25 cma

The AWG figure basically stands for a cross-section only. Therefore, any dimension relative to both single wires as well as strands is expressed as such an AWG figure.

Just to make matters more complicated, it is the construction of a strand that has a crucial impact on some of its major properties like flexibility, resistance, conductivity or tensile strength. This aspect has led to the inclusion of the construction whenever an AWG indication is applied. An AWG28 strand, for instance, may consist of seven AWG36 single wires. This is reflected by the designation “AWG28 7/36”.

Practitioners have developed approximations for the quick calculation of strand sizes, which can be employed to a certain extent:

Rule Example
AWG of 7end strand = AWG single wire – 8 AWG single wire = 36
36 – 8 = 28
AWG 7end strand = 28
AWG single wire = AWG of 7end strand + 8 AWG 7end strand = 28
28 + 8 = 36
AWG single wire = 36
AWG of 19end strand = AWG single wire – 12 AWG single wire = 36
36 – 12 = 24
AWG 19end strand = 24
AWG single wire = AWG of 19end strand + 12 AWG 19er strand = 24
24 + 12 = 36
AWG single wire = 36
AWG of 37end strand = AWG single wire – 16 AWG single wire = 26
26 – 16 = 10
AWG 37end strand = 10
AWG single wire = AWG of 37end strand + 16 AWG of 37end strand = 10
10 + 16 = 26
AWG single wire = 26

6 AWG steps down → diameter is doubled
6 AWG steps up → diameter is halved
3 AWG steps down → cross-section is doubled
3 AWG steps up → cross-section is halved

With telephony growing more and more widespread in the middle of the 19th century, the wire industry experienced an extraordinary technological boost. Industry and commerce were using completely different units of measurement at the time. Joseph Rogers Brown contributed to making the American Wire Gauge system the predominant measuring tool, which lead to an increased standardization in this field. This development has continued to influence the entire product range when it comes to wires made from non-ferrous metals.

Ongoing technological progress has caused some fundamental changes to the wire drawing process. Fixed definitions have partly been superseded by individual solutions. This has rendered the drawing process more flexible across the board, thus also facilitating the production of wires beyond the standard AWG sizes. In spite of AWG still being a common scaling factor for cable sizes, it is more and more replaced by the metric system.

Whenever characterizing our wires and strands, we always indicate both units of measurement as far as available.

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