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

Gague (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

Gauge NumberStandard Steel (mm)Galvanized Steel (mm)Stainless Steel (mm)Aluminum, Brass, Copper (mm)
36.0735.827
45.0955.9545.189
55.3145.5554.62
64.9355.1594.115
74.5544.7633.665
84.1764.1913.264
93.7973.8913.9672.906
103.4163.513.5712.588
113.0383.1323.1752.304
122.6572.7532.7792.052
132.2782.3722.381.829
141.8971.9941.9841.628
151.7091.8031.7861.45
161.5191.6131.5881.29
171.3671.4611.4271.151
181.2141.3111.271.024
191.0621.1581.110.912
200.9121.0060.9530.813
210.8360.930.8740.724
220.7590.8530.7920.643
230.6830.7770.7140.574
240.6070.7010.6350.536
250.5310.6270.5560.455
260.4550.5510.4750.404
270.4170.5130.4370.361
280.3780.4750.3960.32
290.3430.4370.3580.287
300.3050.3990.3180.254
310.2670.3610.2770.226
320.2460.340.2590.203
330.2290.2390.18
340.2080.2180.16
350.1910.1980.142
360.170.1780.127
370.1630.1680.113
380.170.1570.101

Sheet Metal Gauge to inch

Gauge NumberStandard Steel (in)Galvanized Steel (in)Stainless Steel (in)Aluminum, Brass, Copper (in)
30.23910.2294
40.22420.23440.2043
50.20920.21870.1819
60.19430.20310.162
70.17930.18750.1443
80.16440.1650.1285
90.14950.15320.15620.1144
100.13450.13820.14060.1019
110.11960.12330.1250.0907
120.10460.10840.10940.0808
130.08970.09340.09370.072
140.07470.07850.07810.0641
150.06730.0710.07030.0571
160.05980.06350.06250.0508
170.05380.05750.05620.0453
180.04780.05160.050.0403
190.04180.04560.04370.0359
200.03590.03960.03750.032
210.03290.03660.03440.0285
220.02990.03360.03120.0253
230.02690.03060.02810.0226
240.02390.02760.0250.0211
250.02090.02470.02190.0179
260.01790.02170.01870.0159
270.01640.02020.01720.0142
280.01490.01870.01560.0126
290.01350.01720.01410.0113
300.0120.01570.01250.01
310.01050.01420.01090.0089
320.00970.01340.01020.008
330.0090.00940.0071
340.00820.00860.0063
350.00750.00780.0056
360.00670.0070.005
370.00640.00660.00445
380.00670.00620.00396

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