Sheet Metal Thickness Conversion Chart: Galvanized Steel, Stainless Steel, Aluminum

In sheet metal work, the term "gauge" is frequently employed to specify thickness. Gauges are the units used to indicate the thickness of a metal sheet.

Gauge (Ga.) is a unit of measurement for diameters originating in North America, part of the Browne & Sharpe metering system. Initially utilized in fields like medicine and jewelry, the gauge system operates on an inverse relationship: the higher the number, the thinner the diameter. This system now also denotes thickness.

Ga. measurements differ from inches and lack a direct conversion formula. Even if two materials, like non-ferrous metal and steel, share the same gauge, their actual thicknesses vary.

Refer to the chart below for the conversion between gauge measurements and millimeters/inches for various sheet metal materials.

Sheet Metal Gauge to mm

Gauge Number	Standard Steel (mm)	Galvanized Steel (mm)	Stainless Steel (mm)	Aluminum, Brass, Copper (mm)
3	6.073			5.827
4	5.095		5.954	5.189
5	5.314		5.555	4.62
6	4.935		5.159	4.115
7	4.554		4.763	3.665
8	4.176		4.191	3.264
9	3.797	3.891	3.967	2.906
10	3.416	3.51	3.571	2.588
11	3.038	3.132	3.175	2.304
12	2.657	2.753	2.779	2.052
13	2.278	2.372	2.38	1.829
14	1.897	1.994	1.984	1.628
15	1.709	1.803	1.786	1.45
16	1.519	1.613	1.588	1.29
17	1.367	1.461	1.427	1.151
18	1.214	1.311	1.27	1.024
19	1.062	1.158	1.11	0.912
20	0.912	1.006	0.953	0.813
21	0.836	0.93	0.874	0.724
22	0.759	0.853	0.792	0.643
23	0.683	0.777	0.714	0.574
24	0.607	0.701	0.635	0.536
25	0.531	0.627	0.556	0.455
26	0.455	0.551	0.475	0.404
27	0.417	0.513	0.437	0.361
28	0.378	0.475	0.396	0.32
29	0.343	0.437	0.358	0.287
30	0.305	0.399	0.318	0.254
31	0.267	0.361	0.277	0.226
32	0.246	0.34	0.259	0.203
33	0.229		0.239	0.18
34	0.208		0.218	0.16
35	0.191		0.198	0.142
36	0.17		0.178	0.127
37	0.163		0.168	0.113
38	0.17		0.157	0.101

Sheet Metal Gauge to inch

Gauge Number	Standard Steel (in)	Galvanized Steel (in)	Stainless Steel (in)	Aluminum, Brass, Copper (in)
3	0.2391			0.2294
4	0.2242		0.2344	0.2043
5	0.2092		0.2187	0.1819
6	0.1943		0.2031	0.162
7	0.1793		0.1875	0.1443
8	0.1644		0.165	0.1285
9	0.1495	0.1532	0.1562	0.1144
10	0.1345	0.1382	0.1406	0.1019
11	0.1196	0.1233	0.125	0.0907
12	0.1046	0.1084	0.1094	0.0808
13	0.0897	0.0934	0.0937	0.072
14	0.0747	0.0785	0.0781	0.0641
15	0.0673	0.071	0.0703	0.0571
16	0.0598	0.0635	0.0625	0.0508
17	0.0538	0.0575	0.0562	0.0453
18	0.0478	0.0516	0.05	0.0403
19	0.0418	0.0456	0.0437	0.0359
20	0.0359	0.0396	0.0375	0.032
21	0.0329	0.0366	0.0344	0.0285
22	0.0299	0.0336	0.0312	0.0253
23	0.0269	0.0306	0.0281	0.0226
24	0.0239	0.0276	0.025	0.0211
25	0.0209	0.0247	0.0219	0.0179
26	0.0179	0.0217	0.0187	0.0159
27	0.0164	0.0202	0.0172	0.0142
28	0.0149	0.0187	0.0156	0.0126
29	0.0135	0.0172	0.0141	0.0113
30	0.012	0.0157	0.0125	0.01
31	0.0105	0.0142	0.0109	0.0089
32	0.0097	0.0134	0.0102	0.008
33	0.009		0.0094	0.0071
34	0.0082		0.0086	0.0063
35	0.0075		0.0078	0.0056
36	0.0067		0.007	0.005
37	0.0064		0.0066	0.00445
38	0.0067		0.0062	0.00396

The above is the sheet metal specification and thickness table. If you require sheet metal machining services, feel free to reach out to Richconn. We specialize in sheet metal processing and can assist with your specific needs.

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