Wire & Sheet Gauge Conversion Chart

Gauge numbers to millimetres for SWG, AWG, BWG, US steel, galvanised and stainless sheet, and AWG wire to metric cable sizes.

The same gauge number means a different thickness in each system - always confirm in mm.

Wire gauge plate - measure in the slot

Gauge	SWG mm	SWG inch	AWG (B&S) mm	BWG mm	US steel sheet mm	Galvanised sheet mm	Stainless sheet mm
7/0	12.70	0.5000	-	-	-	-	-
6/0	11.79	0.4640	-	-	-	-	-
5/0	10.97	0.4320	-	-	-	-	-
4/0	10.16	0.4000	11.68	11.53	-	-	-
3/0	9.45	0.3720	10.40	10.79	-	-	-
2/0	8.84	0.3480	9.27	9.65	-	-	-
0	8.23	0.3240	8.25	8.64	-	-	-
1	7.62	0.3000	7.35	7.62	-	-	-
2	7.01	0.2760	6.54	7.21	-	-	-
3	6.40	0.2520	5.83	6.58	6.07	-	-
4	5.89	0.2320	5.19	6.05	5.69	-	-
5	5.38	0.2120	4.62	5.59	5.31	-	-
6	4.88	0.1920	4.12	5.16	4.94	-	-
7	4.47	0.1760	3.66	4.57	4.55	-	-
8	4.06	0.1600	3.26	4.19	4.18	4.27	4.37
9	3.66	0.1440	2.91	3.76	3.80	3.89	-
10	3.25	0.1280	2.59	3.40	3.42	3.51	3.57
11	2.95	0.1160	2.30	3.05	3.04	3.13	3.17
12	2.64	0.1040	2.05	2.77	2.66	2.75	2.78
13	2.34	0.0920	1.83	2.41	2.28	2.37	-
14	2.03	0.0800	1.63	2.11	1.90	1.99	1.98
15	1.83	0.0720	1.45	1.83	1.71	1.80	-
16	1.63	0.0640	1.29	1.65	1.52	1.61	1.59
17	1.42	0.0560	1.15	1.47	1.37	1.46	-
18	1.22	0.0480	1.02	1.24	1.21	1.31	1.27
19	1.02	0.0400	0.912	1.07	1.06	1.16	-
20	0.914	0.0360	0.812	0.889	0.912	1.01	0.952
21	0.813	0.0320	0.723	0.813	0.836	0.930	-
22	0.711	0.0280	0.644	0.711	0.759	0.853	0.794
23	0.610	0.0240	0.573	0.635	0.683	0.777	-
24	0.559	0.0220	0.511	0.559	0.607	0.701	0.635
25	0.508	0.0200	0.455	0.508	0.531	0.627	-
26	0.457	0.0180	0.405	0.457	0.455	0.551	0.476
27	0.417	0.0164	0.361	0.406	0.417	0.513	-
28	0.376	0.0148	0.321	0.356	0.378	0.475	0.397
29	0.345	0.0136	0.286	0.330	0.343	0.437	-
30	0.315	0.0124	0.255	0.305	0.305	0.399	0.318
31	0.295	0.0116	0.227	0.254	-	-	-
32	0.274	0.0108	0.202	0.229	-	-	-
33	0.254	0.0100	0.180	0.203	-	-	-
34	0.234	0.0092	0.160	0.178	-	-	-
35	0.213	0.0084	0.143	0.127	-	-	-
36	0.193	0.0076	0.127	0.102	-	-	-
37	0.173	0.0068	0.113	-	-	-	-
38	0.152	0.0060	0.101	-	-	-	-
39	0.132	0.0052	0.090	-	-	-	-
40	0.122	0.0048	0.080	-	-	-	-

AWG	Dia mm	Area mm2	Nearest metric cable mm2
4/0 AWG	11.68	107.2	120
3/0 AWG	10.40	85.0	95
2/0 AWG	9.27	67.4	70
0 AWG	8.25	53.5	50
1 AWG	7.35	42.4	50
2 AWG	6.54	33.6	35
3 AWG	5.83	26.7	25
4 AWG	5.19	21.2	25
5 AWG	4.62	16.8	16
6 AWG	4.12	13.3	16
7 AWG	3.66	10.5	10
8 AWG	3.26	8.37	10
9 AWG	2.91	6.63	6
10 AWG	2.59	5.26	6
11 AWG	2.30	4.17	4
12 AWG	2.05	3.31	4
13 AWG	1.83	2.62	2.5
14 AWG	1.63	2.08	2.5
15 AWG	1.45	1.65	1.5
16 AWG	1.29	1.31	1.5
17 AWG	1.15	1.04	1
18 AWG	1.02	0.82	0.75
19 AWG	0.912	0.65	0.75
20 AWG	0.812	0.52	0.5
21 AWG	0.723	0.41	0.5
22 AWG	0.644	0.33	-
23 AWG	0.573	0.26	-
24 AWG	0.511	0.20	-

Gauge system	Where you meet it
SWG (Standard Wire Gauge)	British wire, sheet, strip and tube - older drawings, fencing and binding wire, welding rod
AWG (American / Brown & Sharpe)	Electrical copper wire, US aluminium, brass and copper sheet
BWG (Birmingham / Stubs)	Tube wall thickness - boiler and heat-exchanger tube, hypodermic tube
US steel sheet (Manufacturers' Standard)	Black and cold-rolled steel sheet from the US
Galvanised sheet gauge	US galvanised sheet - thicker than plain steel of the same number
Stainless sheet gauge	US stainless sheet - close to fractions of an inch
Metric (mm)	Everything sold locally today - quote the thickness in mm to avoid mistakes