When working with sheet metal, the word “gauge” is frequently employed. For instance, someone unfamiliar with the gauge system might not understand what 18 gauge steel means. As a resource, this blog offers a sheet metal gauge chart and an explanation of the gauge system.
How is Sheet Metal Gauges Used?
The thickness of a sheet of metal is specified using gauges. The values of gauges are independent of the metric and conventional measurement systems. Using a gauge conversion chart, it is possible to determine the true thickness of sheet metal in inches or millimeters. A gauge conversion chart shows that, for example, 18 gauge steel = 0.0478 inches or 1.214 millimeters. The measures themselves are unaffected by the gauge number “18.”
Different gauge systems are in use today, with specific gauge names being used for specific metal types. For instance, according to the one gauge system, 18 gauge steel is 0.0478 inches thick while 18 gauge aluminum is 0.0403 inches thick. Because of the various thicknesses, a gauge chart should be utilized to ensure that the metal meets the required specifications.
History of the Gauge System
The gauge system has a lengthy history in metal manufacturing. It most likely originated in the British wire industry before the standard and metric measurement systems were widely used. Gauges were used to specify the diameter of the metal wire being drawn at the time. Since then, it has been a typical method of describing the thickness of wire and sheet metal.
Sheet Metal Gauge Charts
To establish the metal gauge you need, use these sheet metal gauge charts:
Jump to:
Mild Steel Gauge Chart
Aluminum Gauge Chart
Stainless Steel Gauge Chart
Galvanized Steel Gauge Chart
Brass Gauge Chart
Copper Gauge Chart
| Mild Steel Gauge Chart* | ||
| GaugeNumber | Inches | MM |
| 7 | .1793 | 4.554 |
| 8 | .1644 | 4.175 |
| 9 | .1495 | 3.797 |
| 10 | .1345 | 3.416 |
| 11 | .1196 | 3.038 |
| 12 | .1046 | 2.656 |
| 14 | .0747 | 1.897 |
| 16 | .0598 | 1.518 |
| 18 | .0478 | 1.214 |
| 20 | .0359 | .911 |
| 22 | .0299 | .759 |
| 24 | .0239 | .607 |
| 26 | .0179 | .454 |
| 28 | .0149 | .378 |
Buy Mild Steel
| Aluminum Gauge Chart* | ||
| GaugeNumber | Inches | MM |
| 7 | .1443 | 3.665 |
| 8 | .1285 | 3.264 |
| 9 | .1144 | 2.906 |
| 10 | .1019 | 2.588 |
| 11 | .09074 | 2.305 |
| 12 | .08081 | 2.053 |
| 14 | .06408 | 1.628 |
| 16 | .05082 | 1.291 |
| 18 | .04030 | 1.024 |
| 20 | .03196 | .812 |
| 22 | .02535 | .644 |
| 24 | .02010 | .511 |
| 26 | .01594 | .405 |
| 28 | .01264 | .321 |
| 30 | .01003 | .255 |
Buy Aluminum
| Stainless Steel Gauge Chart* | ||
| GaugeNumber | Inches | MM |
| 8 | .17187 | 4.365 |
| 9 | .15625 | 3.968 |
| 10 | .14062 | 3.571 |
| 11 | .125 | 3.175 |
| 12 | .10937 | 2.778 |
| 14 | .07812 | 1.984 |
| 16 | .0625 | 1.587 |
| 18 | .050 | 1.270 |
| 20 | .0375 | .9525 |
| 22 | .03125 | .7937 |
| 24 | .025 | .635 |
| 26 | .01875 | .476 |
| 28 | .01562 | .396 |
| 30 | .0125 | .3175 |
Buy Stainless Steel
| Galvanized Steel Gauge Chart* | ||
| GaugeNumber | Inches | MM |
| 8 | .1681 | 4.269 |
| 9 | .1532 | 3.891 |
| 10 | .1382 | 3.510 |
| 11 | .1233 | 3.1318 |
| 12 | .1084 | 2.753 |
| 14 | .0785 | 1.9939 |
| 16 | .0635 | 1.6129 |
| 18 | .0516 | 1.310 |
| 20 | .0396 | 1.005 |
| 22 | .0336 | .853 |
| 24 | .0276 | .701 |
| 26 | .0217 | .551 |
| 28 | .0187 | .474 |
| 30 | .0157 | .398 |
Buy Galvanized Steel
| Brass Gauge Chart* | ||
| GaugeNumber | Inches | MM |
| 7 | .1443 | 3.665 |
| 8 | .1285 | 3.264 |
| 9 | .1144 | 2.906 |
| 10 | .1019 | 2.588 |
| 11 | .09074 | 2.305 |
| 12 | .08081 | 2.053 |
| 14 | .06408 | 1.628 |
| 16 | .05082 | 1.291 |
| 18 | .04030 | 1.024 |
| 20 | .03196 | .812 |
| 22 | .02535 | .644 |
| 24 | .02010 | .511 |
| 26 | .01594 | .405 |
| 28 | .01264 | .321 |
| 30 | .01003 | .255 |
Buy Brass
| Copper Gauge Chart* | ||
| GaugeNumber | Inches | MM |
| 7 | .180 | 4.572 |
| 8 | .165 | 4.191 |
| 9 | .148 | 3.759 |
| 10 | .134 | 3.404 |
| 11 | .120 | 3.048 |
| 12 | .109 | 2.769 |
| 14 | .083 | 2.108 |
| 16 | .065 | 1.651 |
| 18 | .049 | 1.245 |
| 20 | .035 | .889 |
| 22 | .028 | .711 |
| 24 | .022 | .559 |
| 26 | .018 | .457 |
| 28 | .014 | .356 |
| 30 | .012 | .305 |