Measurements of steel sheet thicknesses in gauge numbers, and their equivalent weight and thicknesses:

Gauge Number	Steel Weight in pounds per square foot	US Standard Gauge: thickness in inches	Manufacturers' Standard: thickness in inches	Galvanized Sheet: weight in lbs/sq ft	Stainless Steel: weight in lbs/sq ft
7/0	20.00	0.5000	.....	.....	.....
6/0	18.75	0.4687	.....	.....	.....
5/0	17.50	0.4375	.....	.....	.....
4/0	16.25	0.4062	.....	.....	.....
3/0	15.00	0.3750	.....	.....	.....
2/0	13.75	0.3437	.....	.....	.....
0	12.50	0.3125	.....	.....	.....
1	11.25	0.2812	.....	.....	.....
2	10.62	0.2656	.....	.....	.....
3	10.00	0.2500	0.2391	.....	.....
4	9.37	0.2344	0.2242	.....	.....
5	8.75	0.2187	0.2092	.....	.....
6	8.12	0.2031	0.1943	.....	.....
7	7.50	0.1875	0.1793	.....	.....
8	6.87	0.1719	0.1644	.....	.....
9	6.25	0.1562	0.1495	.....	.....
10	5.62	0.1406	0.1345	5.7812	5.7937
11	5.00	0.1250	0.1196	5.1562	5.1500
12	4.37	0.1094	0.1046	4.5312	4.5063
13	3.75	0.0937	0.0897	3.9062	3.8625
14	3.12	0.0781	0.0747	3.2812	3.2187
15	2.81	0.0703	0.0673	2.9687	2.8968
16	2.50	0.0625	0.0598	2.6562	2.5750
17	2.25	0.0562	0.0538	2.4062	2.3175
18	2.00	0.0500	0.0478	2.1562	2.0600
19	1.75	0.0437	0.0418	1.9062	1.8025
20	1.50	0.0375	0.0359	1.6562	1.5450
21	1.37	0.0344	0.0329	1.5312	1.4160
22	1.25	0.0312	0.0299	1.4062	1.2875
23	1.12	0.0281	0.0269	1.2812	1.1587
24	1.00	0.0250	0.0239	1.1562	1.0300
25	0.875	0.0219	0.0209	1.0312	0.9013
26	0.750	0.0187	0.0179	0.9062	0.7725
27	0.687	0.0172	0.0164	0.8437	0.7081
28	0.625	0.0156	0.0149	0.7812	0.6438
29	0.562	0.0141	0.0135	0.7187	0.5794
30	0.500	0.0125	0.0120	0.6562	0.5150
31	0.437	0.0109	0.0105	.....	.....
32	0.406	0.0102	0.0097	.....	.....
33	0.375	0.0094	0.0090	.....	.....
34	0.344	0.0086	0.0082	.....	.....
35	0.312	0.0078	0.0075	.....	.....
36	0.281	0.0070	0.0067	.....	.....
37	0.266	0.0066	0.0064	.....	.....
38	0.250	0.0062	0.0060	.....	.....
39	0.234	0.0059	.....	.....	.....
40	0.219	0.0055	.....	.....	.....
41	0.211	0.0053	.....	.....	.....
42	0.203	0.0051	.....	.....	.....
43	0.195	0.0049	.....	.....	.....
44	0.187	0.0047	.....	.....	.....

Also see forge, gauge, welding,wire, a chart of wire gauges, and the names of various metals, techniques, etc.

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