Conversion table: American Wire Gauge [AWG] and metric wire standards

The American Wire Gauge is a measure for how thick a wire is. The number was originally related the amount of stretching that was needed to produce such a wire. The higher the number the thinner the wire.

The metric system outside of the Americas uses the cross sectional area in mm2 to describe how thick a wire is. That cross section is directly related to the resistance of the wire.

The table below provides a conversion between the two units. From the below table one could get the impression that there are more wire diameters in the American system. The opposite is however true. There are theoretically an infinite amount of diameters in the metric system as the measure is directly related to the size. From an engineering point of view it makes however sense to use standard sizes and they are shown below.

AWG
value		Diameter
[inch]		Diameter
[mm]		cross section
[mm2]		Copper resistance
[ohm/km]		common metric equivalent
[mm2]		Notes
1 0.2893 7.348 42.4 0.406  
2 0.2576 6.543 33.6 0.512   Standard US/Canada installation wire 125A
3 0.2294 5.826 26.6 0.646   Standard US/Canada installation wire 100A
4 0.2043 5.189 21.2 0.815   Standard US/Canada installation wire 85A
5 0.1819 4.621 16.8 1.028  
6 0.1620 4.115 13.3 1.296  
7 0.1443 3.665 10.5 1.634  
8 0.1285 3.264 8.37 2.061   Standard US/Canada installation wire 50A
9 0.1144 2.906 6.63 2.599 6.0 Standard European installation wire 30A
10 0.1019 2.588 5.26 3.277   Standard US/Canada installation wire 30A
11 0.0907 2.305 4.17 4.132 4.0
12 0.0808 2.053 3.31 5.211   Standard US/Canada installation wire 20A
13 0.0720 1.828 2.62 6.571 2.5 Thin loudspeaker cable, Standard European installation wire 16A
14 0.0641 1.628 2.08 8.286   Standard US/Canada installation wire 15A
15 0.0571 1.450 1.65 10.45 1.5 Standard European installation wire 10A/16A
16 0.0508 1.291 1.31 13.17  
17 0.0453 1.150 1.04 16.61 1.0
18 0.0403 1.024 0.823 20.95 0.75 control wires heat pumps
19 0.0359 0.912 0.653 26.42  
20 0.0320 0.812 0.518 33.31 0.5
21 0.0285 0.723 0.410 42.00  
22 0.0253 0.644 0.326 52.96   common control wires for heating systems
23 0.0226 0.573 0.258 66.79  
24 0.0201 0.511 0.205 84.22 0.25 Phone line wire
25 0.0179 0.455 0.162 106.2  
26 0.0159 0.405 0.129 133.9 0.14 Ethernet, some phone lines, hobby electronics
27 0.0142 0.361 0.102 168.9  
28 0.0126 0.321 0.0810 212.9 0.09
29 0.0113 0.286 0.0642 268.5  
30 0.0100 0.255 0.0509 338.6  
31 0.00893 0.227 0.0404 426.9  
32 0.00795 0.202 0.0320 538.3  


Modern wires for north american household installations have color coded outer sleeves to make it easier to identify them:

White=15A (or 40A and more but they will be a lot thicker).
Yellow=20A (sometimes red)
Orange=30A

Note that this color code is a common convention but not a requirement. Read the package label or measure the copper diameter to be sure.

© Guido Socher, Version: 2017-03-30