Enter a wire gauge (AWG) or a cross-section in mm² and get the exact conductor area and diameter, the nearest gauge, and the standard ferrule size it takes. AWG values are calculated from the gauge definition, and the ferrule sizes are the standard metric series. Colours are deliberately not shown: they vary by manufacturer, so confirm the size printed on the ferrule.
Reference tables
AWG to mm² and diameter, with the ferrule size each takes
AWG
Area (mm²)
Diameter (mm)
Ferrule size (mm²)
AWG 4/0
107.219
11.684
120
AWG 3/0
85.029
10.405
95
AWG 2/0
67.431
9.266
70
AWG 1/0
53.475
8.251
70
AWG 1
42.408
7.348
50
AWG 2
33.631
6.544
35
AWG 3
26.67
5.827
35
AWG 4
21.151
5.189
25
AWG 5
16.773
4.621
16
AWG 6
13.302
4.115
16
AWG 7
10.549
3.665
16
AWG 8
8.366
3.264
10
AWG 9
6.634
2.906
10
AWG 10
5.261
2.588
6
AWG 11
4.172
2.305
4
AWG 12
3.309
2.053
4
AWG 13
2.624
1.828
2.5
AWG 14
2.081
1.628
2.5
AWG 15
1.65
1.45
2.5
AWG 16
1.309
1.291
1.5
AWG 17
1.038
1.15
1
AWG 18
0.823
1.024
1
AWG 19
0.653
0.912
0.75
AWG 20
0.518
0.812
0.5
AWG 21
0.41
0.723
0.5
AWG 22
0.326
0.644
0.34
AWG 23
0.258
0.573
0.25
AWG 24
0.205
0.511
0.25
AWG 25
0.162
0.455
0.25
AWG 26
0.129
0.405
0.14
AWG 27
0.102
0.361
0.14
AWG 28
0.081
0.321
0.14
AWG 29
0.064
0.286
0.14
AWG 30
0.051
0.255
0.14
AWG 31
0.04
0.227
0.14
AWG 32
0.032
0.202
0.14
Calculated from the AWG definition, so the finest gauges can differ from tables that round the diameter first by under 1%.
AWG is defined by a formula: the diameter of gauge n is 0.127 mm x 92 raised to (36 - n) / 39, and the area is pi / 4 times that diameter squared. That gives AWG 20 as 0.518 mm², AWG 18 as 0.823 mm², AWG 16 as 1.31 mm², AWG 14 as 2.08 mm² and AWG 12 as 3.31 mm². Every three gauges halves the area, and every six halves the diameter. The calculator above does this for any gauge from 4/0 to 40.
What ferrule size do I need for a given wire?
A ferrule is sized to the stripped conductor cross-section. Work out the conductor area (from the AWG or the mm² marked on the wire), then choose the smallest standard ferrule size the conductor fits. This calculator suggests that size and shows the sizes either side. Check the wire range printed on the ferrule maker's datasheet, because the ferrule and the crimp tool together decide what is acceptable.
Why does AWG 20 use a 0.5 mm² ferrule when AWG 20 is 0.518 mm²?
Because the conductor is only about 3.5% over the nominal ferrule size, and stranded copper compresses in the crimp. Ferrule makers commonly pair AWG 20 with 0.5 mm². The calculator applies a rule of thumb of up to 5% over a standard size, so AWG 20 takes 0.5 mm² and AWG 18 (0.823 mm², about 10% over 0.75) takes 1.0 mm². That 5% allowance is this tool's own rule, not part of a standard, so the manufacturer's wire range governs.
How do I size a twin ferrule for two wires?
A twin ferrule carries two conductors side by side and is sized per conductor, not for their combined area. Two AWG 18 wires take a twin ferrule rated for two 1.0 mm² conductors, not a single 1.5 mm² or 2.5 mm² ferrule. Twin ferrules are made in a narrower range of sizes than single ones, so check the maker's range and use the matching crimp tool.
What color is each ferrule size?
The calculator does not show colours on purpose. DIN 46228-4 sets a reference colour per size and most brands follow it, but adherence varies by manufacturer and published charts disagree outside the common sizes, so a colour is a visual check and never the order specification. Confirm the size printed on the ferrule or its listing. Our wire ferrule sizing guide explains this in detail.
Can KKM source a ferrule that is not listed here?
Yes. Email the wire gauge or cross-section, the insulated or uninsulated style, and the quantity to orderdesk@kkmsolutions.com. We source per order across our supplier network, not only what is indexed on the site.
