Home › Charts › Aluminum Gauge Chart
Aluminum Sheet Metal Gauge Chart
16 gauge aluminum = 0.0508 in = 1.29 mm — the thinnest 16 gauge of the four metals.
Full chart below: every gauge from 7 to 30 in inches and millimetres, under Brown & Sharpe / AWG (ASTM B209), t = 0.005 x 92^((36-n)/39).
Aluminum sheet borrows its gauge system from wire. The Brown & Sharpe gauge, governed for sheet by ASTM B209, is the same geometric series used for American Wire Gauge, and it produces the thinnest readings of the four metals on this site: at 16 gauge, aluminum is 0.0508 inches against steel's 0.0598 — and aluminum is also far less dense, so an aluminum sheet is dramatically lighter than a steel sheet of the same gauge and size.
The range runs from 7 gauge at 0.1443 inches to 30 gauge at 0.0100 inches. Aluminum is also the metal most often sold by decimal thickness instead of gauge — 0.040, 0.050, 0.063, and 0.080 inches are stock callouts — and the table below lets you move between the two languages.
Gauge converter
Aluminum gauge thickness chart
| Gauge | Thickness | Relative thickness |
|---|---|---|
| 7 | 0.1443 | |
| 8 | 0.1285 | |
| 9 | 0.1144 | |
| 10 | 0.1019 | |
| 11 | 0.0907 | |
| 12 | 0.0808 | |
| 13 | 0.0720 | |
| 14 | 0.0641 | |
| 15 | 0.0571 | |
| 16 | 0.0508 | |
| 17 | 0.0453 | |
| 18 | 0.0403 | |
| 19 | 0.0359 | |
| 20 | 0.0320 | |
| 21 | 0.0285 | |
| 22 | 0.0253 | |
| 23 | 0.0226 | |
| 24 | 0.0201 | |
| 25 | 0.0179 | |
| 26 | 0.0159 | |
| 27 | 0.0142 | |
| 28 | 0.0126 | |
| 29 | 0.0113 | |
| 30 | 0.0100 |
The Brown & Sharpe formula
Aluminum is the one system here you can compute instead of look up. Thickness in inches equals 0.005 times 92 raised to the power of (36 minus the gauge number) divided by 39. Run it for 16 gauge and you get 0.0508 inches — the chart value. Because the series is geometric, every step up in gauge number multiplies the thickness by the same factor, about 0.89: each gauge is roughly 11 percent thinner than the one before it, all the way down the table.
That regularity is the fingerprint of a wire gauge. Wire was drawn through dies in repeated passes, and each pass reduced the diameter by a fixed proportion. Sheet aluminum inherited the numbering wholesale, which is why its values never line up with the weight-based steel steps.
Decimal callouts: how aluminum is often sold
Many aluminum suppliers list sheet by decimal thickness, and the common stock sizes sit close to gauge values: 0.040 inches is 18 gauge (0.0403), 0.050 is 16 gauge (0.0508), 0.063 is 14 gauge (0.0641), and 0.080 is 12 gauge (0.0808). When a drawing gives a decimal, the nearest-gauge table below finds the matching gauge; when it gives a gauge, this chart gives the decimal your supplier will actually stock.
One caution: because the steps are a fixed ratio, the absolute gaps shrink fast at thin gauges. The difference between 24 and 26 gauge aluminum is only 0.0042 inches — if a thin part must be a precise thickness, order by decimal and measure on delivery.
Where aluminum gauges get used
Aluminum earns its place where weight or corrosion rules out steel. Signage, trailer skins, boat panels, aircraft and motorsport sheet, and outdoor enclosures are its everyday territory: it does not rust, it cuts and forms easily, and a panel you can carry in one hand replaces a steel panel that takes two people. Common picks: 18 to 20 gauge for signs and light covers, 14 to 16 gauge for trailer and toolbox work, 10 to 12 gauge where the sheet has to carry load or take impacts.
It is also the friendliest metal on this site for home-shop work — it shears, saws, and files without drama — but it is soft. A thin aluminum panel dents where a steel panel of the same gauge would shrug, so for floors, ramps, and work surfaces, step up one or two gauges from what you would use in steel, or switch to tread plate in a decimal thickness.
Nearest aluminum gauge for metric thicknesses
Computed from the chart above: for each common metric size, the published aluminum gauge whose thickness is closest, with its actual thickness.
| Metric thickness | Aluminum |
|---|---|
| 0.5 mm | 24 ga (0.511 mm) |
| 0.8 mm | 20 ga (0.813 mm) |
| 1 mm | 18 ga (1.024 mm) |
| 1.2 mm | 17 ga (1.151 mm) |
| 1.5 mm | 15 ga (1.45 mm) |
| 2 mm | 12 ga (2.052 mm) |
| 2.5 mm | 10 ga (2.588 mm) |
| 3 mm | 9 ga (2.906 mm) |
| 4 mm | 7 ga (3.665 mm) |
Frequently asked questions
How thick is 16 gauge aluminum?
0.0508 inches, which is 1.29 mm. That is the thinnest 16 gauge of the four metals on this site — the same label in galvanized steel is 0.0635 inches, a full 25 percent thicker.
What is the formula for aluminum gauge thickness?
Thickness in inches = 0.005 × 92^((36 − gauge) / 39), the Brown & Sharpe formula. It reproduces every value in the aluminum chart, because the series is geometric: each step is about 11 percent thinner than the last.
What gauge is 0.063 inch aluminum?
Fourteen gauge. The chart value for 14 gauge aluminum is 0.0641 inches, so a 0.063 callout and a 14 gauge sheet are, for ordering purposes, the same stock.
Why is aluminum thinner than steel at the same gauge?
Different systems. Steel's gauge is based on weight per square foot; aluminum borrowed the Brown & Sharpe wire gauge, a geometric ratio series. The two were never reconciled, and aluminum reads thinner at every shared number.
Should I use aluminum or steel for a lightweight panel?
Aluminum, almost always. At the same gauge it is both thinner and made of a much less dense metal, so the finished panel weighs a fraction of the steel version. Step up a gauge or two if the panel needs dent resistance.
Related charts
- Sheet metal gauge chart (all four metals)
- Steel gauge chart
- Stainless steel gauge chart
- Galvanized gauge chart
- Gauge to mm converter
- All charts
Thickness values follow Brown & Sharpe / AWG (ASTM B209), t = 0.005 x 92^((36-n)/39); cross-checked against published supplier charts, November 2026.