Sheet Metal Gauge Thickness Chart (gauge to mm/inch Conversions)

When working with sheet metal, the term “gauge” is often used. Gauge are used to specify the thickness of a metal sheet.

Gauge (Ga.) is a length measurement unit for diameters originating in North America and belongs to the Browne & Sharpe metering system. Originally used in the fields of medicine and jewellery, the larger the number, the smaller the diameter, and now it is also used to indicate the thickness.

Ga. is different from inches, there is no conversion formula. Even when the non-ferrous metal plate and the steel plate are the same Ga., the thickness is actually different.

You can find the gauge to mm / inch conversion for sheet metal by the chart below.

Sheet Metal Gauge to mm
Sheet Metal Gauge to inch

Or you can Download the Sheet Metal Gauge Size Chart PDF. (Click here)

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

FAQ about Gauge Conversion

How many mm is 8 gauge?

For different materials of steel, the same gauge will also correspond to different mm.

Standard Steel: 8 Gauge = 4.176 mm
Stainless Steel: 8 Gauge = 4.191 mm
Aluminum, Brass, Copper: 8 Gauge = 4.115 mm

What is 10 gauge in mm?

Standard Steel: 10 Gauge = 3.416 mm
Galvanized Steel: 10 Gauge = 3.51 mm
Stainless Steel: 10 Gauge = 3.571 mm
Aluminum, Brass, Copper: 10 Gauge = 2.588 mm

What is 16 gauge thickness in mm?

Standard Steel: 16 Gauge = 1.519 mm
Galvanized Steel: 16 Gauge = 1.613 mm
Stainless Steel: 16 Gauge = 1.588 mm
Aluminum, Brass, Copper: 16 Gauge = 1.29 mm