The full chart — gauges 7 to 30
| Gauge | Steel (in) | Steel (mm) | Galvanized (in) | Galvanized (mm) | Stainless (in) | Stainless (mm) | Aluminum (in) | Aluminum (mm) |
|---|---|---|---|---|---|---|---|---|
| 7 | 0.1793 | 4.554 | — | — | 0.1875 | 4.762 | 0.1443 | 3.665 |
| 8 | 0.1644 | 4.176 | 0.1681 | 4.27 | 0.1719 | 4.366 | 0.1285 | 3.264 |
| 9 | 0.1495 | 3.797 | 0.1532 | 3.891 | 0.1563 | 3.97 | 0.1144 | 2.906 |
| 10 | 0.1345 | 3.416 | 0.1382 | 3.51 | 0.1406 | 3.571 | 0.1019 | 2.588 |
| 11 | 0.1196 | 3.038 | 0.1233 | 3.132 | 0.1250 | 3.175 | 0.0907 | 2.304 |
| 12 | 0.1046 | 2.657 | 0.1084 | 2.753 | 0.1094 | 2.779 | 0.0808 | 2.052 |
| 13 | 0.0897 | 2.278 | 0.0934 | 2.372 | 0.0938 | 2.383 | 0.0720 | 1.829 |
| 14 | 0.0747 | 1.897 | 0.0785 | 1.994 | 0.0781 | 1.984 | 0.0641 | 1.628 |
| 15 | 0.0673 | 1.709 | 0.0710 | 1.803 | 0.0703 | 1.786 | 0.0571 | 1.45 |
| 16 | 0.0598 | 1.519 | 0.0635 | 1.613 | 0.0625 | 1.587 | 0.0508 | 1.29 |
| 17 | 0.0538 | 1.367 | 0.0575 | 1.46 | 0.0563 | 1.43 | 0.0453 | 1.151 |
| 18 | 0.0478 | 1.214 | 0.0516 | 1.311 | 0.0500 | 1.27 | 0.0403 | 1.024 |
| 19 | 0.0418 | 1.062 | 0.0456 | 1.158 | 0.0438 | 1.113 | 0.0359 | 0.912 |
| 20 | 0.0359 | 0.912 | 0.0396 | 1.006 | 0.0375 | 0.952 | 0.0320 | 0.813 |
| 21 | 0.0329 | 0.836 | 0.0366 | 0.93 | 0.0344 | 0.874 | 0.0285 | 0.724 |
| 22 | 0.0299 | 0.759 | 0.0336 | 0.853 | 0.0313 | 0.795 | 0.0253 | 0.643 |
| 23 | 0.0269 | 0.683 | 0.0306 | 0.777 | 0.0281 | 0.714 | 0.0226 | 0.574 |
| 24 | 0.0239 | 0.607 | 0.0276 | 0.701 | 0.0250 | 0.635 | 0.0201 | 0.511 |
| 25 | 0.0209 | 0.531 | 0.0247 | 0.627 | 0.0219 | 0.556 | 0.0179 | 0.455 |
| 26 | 0.0179 | 0.455 | 0.0217 | 0.551 | 0.0188 | 0.478 | 0.0159 | 0.404 |
| 27 | 0.0164 | 0.417 | 0.0202 | 0.513 | 0.0172 | 0.437 | 0.0142 | 0.361 |
| 28 | 0.0149 | 0.378 | 0.0187 | 0.475 | 0.0156 | 0.396 | 0.0126 | 0.32 |
| 29 | 0.0135 | 0.343 | 0.0172 | 0.437 | 0.0141 | 0.358 | 0.0113 | 0.287 |
| 30 | 0.0120 | 0.305 | 0.0157 | 0.399 | 0.0125 | 0.318 | 0.0100 | 0.254 |
Galvanized shows a dash at 7 gauge: published galvanized tables start at 8 gauge.
One chart per metal
Steel gauge chart
The weight-based standard (MSG, ASTM A568), with a weight column.
16 ga = 0.0598 in
Galvanized gauge chart
Steel plus a 0.0037 in zinc allowance (ASTM A653). Starts at 8 gauge.
16 ga = 0.0635 in
Stainless steel gauge chart
The fraction-based series (ASTM A480). 16 ga is exactly 1/16 in.
16 ga = 0.0625 in
Aluminum gauge chart
The Brown & Sharpe formula series (ASTM B209). Thinnest and lightest.
16 ga = 0.0508 in
Why one gauge number gives four thicknesses
The gauge systems were set up separately, by different industries, long before decimal thickness callouts became normal. Carbon steel sheet follows the Manufacturers' Standard Gauge, which is based on weight: a sheet one inch thick weighs 41.82 pounds per square foot, and every gauge step is a fixed slice of that weight scale. Galvanized sheet starts from the same steel table and adds 0.0037 inches for the zinc coating, so every galvanized number reads exactly that much thicker than the same steel gauge.
Stainless steel kept an older fraction-based series, which is why its values land on familiar fractions: 16 gauge stainless is exactly 1/16 inch, 0.0625. Aluminum never had a sheet gauge of its own, so it borrowed the Brown & Sharpe wire gauge, a geometric series in which each step multiplies the thickness by the same ratio. That is why aluminum runs thinner than steel at every shared gauge number, and why the gap between the two widens as the numbers climb.
The practical rule: a gauge number means nothing until you name the metal. Every chart on this site keeps the four systems side by side, in inches and millimetres, so you can check the number you were given against the metal you are actually buying.
Working in millimetres?
Use the gauge to mm converter to convert any gauge, or to find the nearest gauge for a metric thickness in each metal.
Thickness values follow Manufacturers' Standard Gauge (ASTM A568) · ASTM A653 (galvanized) · ASTM A480 (stainless) · ASTM B209 (aluminum); cross-checked against published supplier charts, November 2026.