Most UK and foreign customers struggle with AWG sizing when purchasing cut to length electrical wire or electrical cable. American customers, on the other hand, can be stumped when a specific gauge of cable or wire is recommended, and they don't know how to obtain it when faced with mm.

We don't see ourselves casually measuring this in our heads any time we talk with an American customer, so we've put together a conversion table that we'd like to share with you.

What exactly is AWG? The Brown & Sharpe Company, a leading manufacturer of machinist technology in the late 1800s and early 1900s, produced the AWG standard. In 1857, the AWG standard was formally adopted and introduced as the industry standard for sizing. Unfortunately, AWG does not fit comfortably in rounded mm or inches, so a small amount of rounding up or down will often be needed, depending on the need or purpose. The following are the technical formulas for converting between the two: The n gauge wire diameter dn in millimetres (mm) is equal to 0.127mm times 92 raised to the power of 36 minus gauge number n, divided by 39: dn (mm) = 0.127 mm × 92(36-n)/39

AWG #	Diameter (mm)	Diameter (inch)	Area (mm²)	Available Cable Size (mm²)
0000 (4/0)	11.684	0.46	107.2193	120
000 (3/0)	10.4049	0.4096	85.0288	95
00 (2/0)	9.2658	0.3648	67.4309	70
0 (1/0)	8.2515	0.3249	53.4751	70
1	7.3481	0.2893	42.4077	50
2	6.5437	0.2576	33.6308	35
3	5.8273	0.2294	26.6705	35
4	5.1894	0.2043	21.1506	25
5	4.6213	0.1819	16.7732	25
6	4.1154	0.162	13.3018	16
7	3.6649	0.1443	10.5488	16
8	3.2636	0.1285	8.3656	10
9	2.9064	0.1144	6.6342	10
10	2.5882	0.1019	5.2612	6
11	2.3048	0.0907	4.1723	6
12	2.0525	0.0808	3.3088	4
13	1.8278	0.072	2.624	4
14	1.6277	0.0641	2.0809	2.5
15	1.4495	0.0571	1.6502	2.5
16	1.2908	0.0508	1.3087	1.5
17	1.1495	0.0453	1.0378	1.5
18	1.0237	0.0403	0.823	1
19	0.9116	0.0359	0.6527	0.75
20	0.8118	0.032	0.5176	0.75
21	0.7229	0.0285	0.4105	0.5
22	0.6438	0.0253	0.3255	0.5
23	0.5733	0.0226	0.2582	See Below
24	0.5106	0.0201	0.2047	See Below
25	0.4547	0.0179	0.1624	See Below
26	0.4049	0.0159	0.1288	See Below
27	0.3606	0.0142	0.1021	See Below
28	0.3211	0.0126	0.081	See Below
29	0.2859	0.0113	0.0642	See Below
30	0.2546	0.01	0.0509	See Below
31	0.2268	0.0089	0.0404	See Below
32	0.2019	0.008	0.032	See Below
33	0.1798	0.0071	0.0254	See Below
34	0.1601	0.0063	0.0201	See Below
35	0.1426	0.0056	0.016	See Below
36	0.127	0.005	0.0127	See Below
37	0.1131	0.0045	0.01	See Below
38	0.1007	0.004	0.008	See Below
39	0.0897	0.0035	0.0063	See Below
40	0.0799	0.0031	0.005	See Below

Note: When using a cable to control mains voltages (110v, 230v, etc.), the smallest conductor we suggest is 0.5mm for AWG 23 and up. You will want to use smaller cables for audio, video, telephone, and protection cabling because the voltage and current are lower.