Aluminum gauge chart
Aluminium sheet is gauged on the Brown and Sharpe scale, which is the same series as American Wire Gauge and a different one from the Manufacturers' Standard used for steel. The practical consequence is that a gauge number alone does not give you a thickness: 16 gauge aluminium is 0.0508 inches where 16 gauge steel is 0.0598, about 18 percent thicker, so a drawing that says only "16 gauge" is ambiguous until it names the metal.
Aluminium sheet thickness by gauge
Thickness, millimetres and weight per square foot, with the steel thickness at the same gauge number beside it so the difference is visible rather than implied.
| Gauge | Thickness (in) | Thickness (mm) | Weight (lb/ft2) | Steel at same gauge (in) | Steel is |
|---|---|---|---|---|---|
| 3 | 0.2294 | 5.83 | 3.22 | 0.2391 | +4% |
| 4 | 0.2043 | 5.19 | 2.87 | 0.2242 | +10% |
| 5 | 0.1819 | 4.62 | 2.55 | 0.2092 | +15% |
| 6 | 0.1620 | 4.11 | 2.27 | 0.1943 | +20% |
| 7 | 0.1443 | 3.67 | 2.03 | 0.1793 | +24% |
| 8 | 0.1285 | 3.26 | 1.80 | 0.1644 | +28% |
| 9 | 0.1144 | 2.91 | 1.61 | 0.1495 | +31% |
| 10 | 0.1019 | 2.59 | 1.43 | 0.1345 | +32% |
| 11 | 0.0907 | 2.30 | 1.27 | 0.1196 | +32% |
| 12 | 0.0808 | 2.05 | 1.13 | 0.1046 | +29% |
| 13 | 0.0720 | 1.83 | 1.01 | 0.0897 | +25% |
| 14 | 0.0641 | 1.63 | 0.90 | 0.0747 | +17% |
| 15 | 0.0571 | 1.45 | 0.80 | 0.0673 | +18% |
| 16 | 0.0508 | 1.29 | 0.71 | 0.0598 | +18% |
| 17 | 0.0453 | 1.15 | 0.64 | 0.0538 | +19% |
| 18 | 0.0403 | 1.02 | 0.57 | 0.0478 | +19% |
| 19 | 0.0359 | 0.91 | 0.50 | 0.0418 | +16% |
| 20 | 0.0320 | 0.81 | 0.45 | 0.0359 | +12% |
| 21 | 0.0285 | 0.72 | 0.40 | 0.0329 | +15% |
| 22 | 0.0253 | 0.64 | 0.36 | 0.0299 | +18% |
| 23 | 0.0226 | 0.57 | 0.32 | 0.0269 | +19% |
| 24 | 0.0201 | 0.51 | 0.28 | 0.0239 | +19% |
| 25 | 0.0179 | 0.45 | 0.25 | 0.0209 | +17% |
| 26 | 0.0159 | 0.40 | 0.22 | 0.0179 | +13% |
| 27 | 0.0142 | 0.36 | 0.20 | 0.0164 | +15% |
| 28 | 0.0126 | 0.32 | 0.18 | 0.0149 | +18% |
| 29 | 0.0113 | 0.29 | 0.16 | 0.0135 | +19% |
| 30 | 0.0100 | 0.25 | 0.14 | 0.0120 | +20% |
Why aluminium and steel differ at the same gauge
- Gauge scales were set by manufacturers, not by a standards body, and non-ferrous sheet inherited the Brown and Sharpe series while ferrous sheet kept the Manufacturers Standard. Neither was designed to agree with the other.
- Brown and Sharpe is geometric: each gauge step multiplies thickness by about 0.8905, the same ratio as AWG. The steel standard is not geometric, which is why the gap between the two scales changes with gauge number.
- Aluminium is about a third the density of steel, so a sheet of the same thickness weighs roughly 35 percent of the steel one. That is a separate matter from the gauge scale and the two are easy to conflate.
- For anything structural or quoted, specify a decimal thickness rather than a gauge number. A gauge number is shorthand between people who already agree which scale they are using.
Printable aluminium gauge chart
Aluminium sits beside steel, galvanised and stainless on the full sheet metal wall chart.
- Sheet metal gauge chart (PDF): All four materials at every gauge, in inches and millimetres. Free to print and share with attribution.
- Sheet metal weight chart (PDF): Pounds per square foot and full 4x8 sheet weight, aluminium included.
Common questions
How thick is 16 gauge aluminum?
- 0.0508 inches, which is 1.29 millimetres. Steel at the same gauge number is 0.0598 inches, so the steel is about 18 percent thicker.
Is aluminum gauge the same as steel gauge?
- No. Aluminium follows Brown and Sharpe and steel follows the Manufacturers Standard Gauge for Sheet Steel. The same number is a different thickness in each, and the size of the difference changes with the gauge.
What gauge is 1/8 inch aluminum?
- One eighth of an inch is 0.125 inches, which is close to 8 gauge aluminium at 0.1285 inches. For anything that has to fit, quote the decimal rather than the gauge.
Does aluminum gauge use the same scale as wire gauge?
- Yes. Brown and Sharpe is American Wire Gauge, so aluminium sheet and AWG conductors sit on the same geometric series where each step multiplies the thickness or diameter by about 0.8905.