Sheet Metal Gauge Chart
Gauge to decimal inches for carbon steel, galvanized steel, aluminum and stainless. Same gauge number, different thickness, so check the column for your metal.
| Gauge | Carbon steel | Galvanized steel | Aluminum | Stainless |
|---|---|---|---|---|
| 3 ga | 0.2391 | n/a | 0.2294 | 0.2500 |
| 4 ga | 0.2242 | n/a | 0.2043 | 0.2344 |
| 5 ga | 0.2092 | n/a | 0.1819 | 0.2187 |
| 6 ga | 0.1943 | n/a | 0.1620 | 0.2031 |
| 7 ga | 0.1793 | n/a | 0.1443 | 0.1875 |
| 8 ga | 0.1644 | 0.1681 | 0.1285 | 0.1719 |
| 9 ga | 0.1495 | 0.1532 | 0.1144 | 0.1563 |
| 10 ga | 0.1345 | 0.1382 | 0.1019 | 0.1406 |
| 11 ga | 0.1196 | 0.1233 | 0.0907 | 0.1250 |
| 12 ga | 0.1046 | 0.1084 | 0.0808 | 0.1094 |
| 13 ga | 0.0897 | 0.0934 | 0.0720 | 0.0940 |
| 14 ga | 0.0747 | 0.0785 | 0.0641 | 0.0781 |
| 15 ga | 0.0673 | 0.0710 | 0.0571 | 0.0703 |
| 16 ga | 0.0598 | 0.0635 | 0.0508 | 0.0625 |
| 17 ga | 0.0538 | 0.0575 | 0.0453 | 0.0563 |
| 18 ga | 0.0478 | 0.0516 | 0.0403 | 0.0500 |
| 19 ga | 0.0418 | 0.0456 | 0.0359 | 0.0438 |
| 20 ga | 0.0359 | 0.0396 | 0.0320 | 0.0375 |
| 21 ga | 0.0329 | 0.0366 | 0.0285 | 0.0344 |
| 22 ga | 0.0299 | 0.0336 | 0.0253 | 0.0312 |
| 23 ga | 0.0269 | 0.0306 | 0.0226 | 0.0281 |
| 24 ga | 0.0239 | 0.0276 | 0.0201 | 0.0250 |
| 25 ga | 0.0209 | 0.0247 | 0.0179 | 0.0219 |
| 26 ga | 0.0179 | 0.0217 | 0.0159 | 0.0188 |
| 28 ga | 0.0149 | 0.0187 | 0.0126 | 0.0156 |
| 30 ga | 0.0120 | 0.0157 | 0.0100 | 0.0125 |
Nominal values from the standard published charts: Manufacturers' Standard Gauge for steel, galvanized gauge for coated steel, Brown & Sharpe for aluminum. Real sheet runs within a tolerance band around these numbers.
How to use it
Find the gauge on your drawing, then read across to the column for the metal. 14 gauge carbon steel is 0.0747 inch. 14 gauge aluminum is 0.0641. If you order "14 gauge aluminum" and mean the steel number, the part comes out thinner than you expected.
That's why aluminum is almost always bought by decimal: 0.040, 0.063, 0.080, 0.090, 0.125, 0.190. Stainless is still often called out by gauge, and carbon steel by gauge up to 7 or 3/16 inch, then by fraction as plate.
When the number matters
For brake-formed parts, the thickness drives the bend allowance, so a drawing built on the wrong gauge table gives parts that don't fit. For welded work, thin gauge warps easily, and one gauge up can be worth it. When in doubt, put the decimal on the quote request, and we'll match it. The weight calculator will tell you what a sheet at that thickness weighs.
Buying sheet? See aluminum sheet, stainless sheet and hot rolled, cold rolled and galvanized sheet.
Gauge questions
Why is 10 gauge steel a different thickness from 10 gauge aluminum?
Gauge isn't a unit. Steel sheet uses the Manufacturers' Standard Gauge, which is based on weight per square foot, while aluminum is usually quoted on the Brown & Sharpe scale. The same number means a different thickness.
Should I order aluminum by gauge?
Better not. Aluminum sheet is normally sold by decimal thickness (0.063, 0.080, 0.125). Ask for the decimal and there's no room for confusion.
Is 7 gauge sheet or plate?
7 gauge steel is about 0.179 inch, just under 3/16. Most people still call it sheet. At 3/16 inch and thicker, steel is sold as plate by fractional or decimal thickness.
What's the tolerance on a gauge thickness?
Every gauge has a tolerance band set by the product spec, and actual sheet will measure a little over or under the nominal decimal. If the thickness is critical, give us the decimal and the tolerance you need.