IEC Wire Sizes

IEC 60228 is the International Electrotechnical Commission's international standard on conductors of insulated cables.

Among other things, it defines a set of standard wire cross-sectional areas:

International standard wire sizes (IEC 60228)

0.5 mm2	0.75 mm2	1 mm2	1.5 mm2	2.5 mm2	4 mm2
6 mm2	10 mm2	16 mm2	25 mm2	35 mm2	50 mm2
70 mm2	95 mm2	120 mm2	150 mm2	185 mm2	240 mm2
300 mm2	400 mm2	500 mm2	630 mm2	800 mm2	1000 mm2