Sheet Metal Gauge Chart and Gauge to mm Converter
Pick a material and a gauge to get its thickness in inches and mm, or type a thickness to find the nearest gauge. The full chart is below.
This free sheet metal gauge chart and converter turns a gauge number into thickness in inches and millimetres, and turns a thickness back into the nearest gauge, for steel, galvanized steel, stainless steel and aluminum. It also shows the weight per square foot and per square metre for each gauge. It runs in your browser with no sign-up.
Use it as a gauge to mm converter, a mm to gauge lookup, or a printable steel gauge chart for a shop wall or a quote. The page opens with steel selected, and the full chart for the chosen material sits below the converter. The converter does gauge to millimeter conversion in both directions, so you can also convert millimeters to gauge when a drawing gives only a metric thickness.
At a glance
Sheet Metal Gauge Chart is a free browser tool that converts a sheet metal gauge number to thickness in inches and mm, or a thickness in mm or inches to the nearest gauge, for steel, galvanized, stainless and aluminum.
- The converter covers every gauge from 3 to 38, with weight per square foot and per square metre for each gauge.
- 16 gauge steel is 0.0598 in (1.519 mm) thick and weighs 2.442 lb/ft² at a density of 7.85 g/cm³.
- The tool uses 7.85 g/cm³ for steel, 8.00 g/cm³ for stainless 304 and 2.70 g/cm³ for aluminum 6061.
- Entering 1.5 mm in steel returns 16 ga (1.519 mm, 1.3% thicker), with 17 ga (1.367 mm) as the next nearest gauge.
- Each material follows its own gauge standard, so the same gauge number gives a different thickness in steel and aluminum.
Sources: Sheet metal (Wikipedia) (checked 2026-10-15) · Material density chart (AIMS Industrial) (checked 2026-10-15)
How to use the gauge converter
- Choose a Material: Steel (carbon, uncoated), Galvanized steel, Stainless steel or Aluminum. The page opens with Steel selected.
- Choose a mode: Gauge to thickness or Thickness to gauge.
- For Gauge to thickness, type a gauge number. Read the thickness in inches and mm, plus the weight in lb/ft² and kg/m².
- For Thickness to gauge, type a thickness in mm or inches. Read the nearest gauge, the difference, and the next nearest gauge.
- Use the Metric (mm) / Imperial (in) switch at the top to change units.
- Scroll the chart below the converter. Click a row to select that gauge.
- Click Compare all materials to see one table with the thickness of every material for each gauge number.
To keep your work, click Print / save chart. It prints your inputs, the result, the calculation steps, the date and the full chart for the chosen material as a clean table; choose Save as PDF in the print dialog to keep a PDF. Results, charts and printouts are free to use in commercial work such as quotes, client jobs and products, with no attribution required. Copy link gives you a link that reopens the page with the same inputs, and Reset clears the entries.
What does gauge mean in sheet metal
Gauge is a number that stands for a sheet thickness. It is not a measurement in itself, and the same number can mean different thicknesses in different metals. Each material follows its own gauge standard.
Steel sheet uses the Manufacturers’ Standard Gauge (MSG), which is defined by weight. The standard is 41.82 lb per square foot for each inch of thickness. So 16 gauge steel weighs 2.5 lb/ft², which works out to 0.0598 in (1.519 mm). Stainless steel usually uses the U.S. Standard Gauge, where thicknesses are exact fractions of an inch, such as 16 gauge = 1/16 in. Aluminum uses the Brown & Sharpe gauge, also called American Wire Gauge.
Why does a higher gauge mean thinner metal
A higher gauge number means thinner sheet. The numbers count down from thick to thin, so 10 gauge is much thicker than 20 gauge. This is why 18 ga to mm gives a smaller value than 10 ga in mm.
The tool calculates weight per area as thickness times density. Steel and galvanized steel use 7.85 g/cm³, stainless (304) uses 8.00 g/cm³, and aluminum (6061) uses 2.70 g/cm³. Because of this, the same gauge number gives a lighter sheet of aluminum than steel. Galvanized sheet is about 0.0037 in thicker than the same uncoated steel gauge, because the zinc coating adds to the thickness.
Sheet metal thickness guide: common gauges
The table below is a quick sheet metal thickness guide for the gauges most often used in fabrication, so you can compare materials at a glance. Each value comes from the same tables the converter uses; the tool above covers every gauge from 3 to 38 and adds the weight per square foot and square metre.
| Gauge | Steel (MSG) | Galvanized | Stainless (USSG) | Aluminum (B&S) |
|---|---|---|---|---|
| 10 | 0.1345 in / 3.416 mm | 0.1382 in / 3.510 mm | 0.1406 in / 3.572 mm | 0.1019 in / 2.588 mm |
| 11 | 0.1196 in / 3.038 mm | 0.1233 in / 3.132 mm | 0.1250 in / 3.175 mm | 0.0907 in / 2.305 mm |
| 12 | 0.1046 in / 2.657 mm | 0.1084 in / 2.753 mm | 0.1094 in / 2.778 mm | 0.0808 in / 2.053 mm |
| 14 | 0.0747 in / 1.897 mm | 0.0785 in / 1.994 mm | 0.0781 in / 1.984 mm | 0.0641 in / 1.628 mm |
| 16 | 0.0598 in / 1.519 mm | 0.0635 in / 1.613 mm | 0.0625 in / 1.588 mm | 0.0508 in / 1.291 mm |
| 18 | 0.0478 in / 1.214 mm | 0.0516 in / 1.311 mm | 0.0500 in / 1.270 mm | 0.0403 in / 1.024 mm |
| 20 | 0.0359 in / 0.912 mm | 0.0396 in / 1.006 mm | 0.0375 in / 0.953 mm | 0.0320 in / 0.812 mm |
| 22 | 0.0299 in / 0.759 mm | 0.0336 in / 0.853 mm | 0.0313 in / 0.794 mm | 0.0253 in / 0.644 mm |
| 24 | 0.0239 in / 0.607 mm | 0.0276 in / 0.701 mm | 0.0250 in / 0.635 mm | 0.0201 in / 0.511 mm |
| 26 | 0.0179 in / 0.455 mm | 0.0217 in / 0.551 mm | 0.0187 in / 0.476 mm | 0.0159 in / 0.405 mm |
Sources
Data and rules used by this tool (checked October 2026):
Frequently asked questions
How thick is 16 gauge steel?
16 gauge steel is 0.0598 in (1.519 mm) thick. It weighs 2.442 lb/ft² (11.92 kg/m²) at a density of 7.85 g/cm³. The MSG nominal weight is 2.501 lb/ft².
How do I convert gauge to mm?
Select your material, enter the gauge number under Gauge to thickness, and read the mm value. The conversion depends on the material, so the same gauge gives different mm values for steel and aluminum. For example, 10 ga in steel is 3.416 mm.
What is 10 ga in mm?
10 gauge steel is 0.1345 in, which is 3.416 mm. In stainless steel 10 gauge is 9/64 in (3.572 mm), and in aluminum it is 0.1019 in (2.588 mm).
What is 18 ga in mm?
18 gauge steel is 0.0478 in, which is 1.214 mm. Other materials use different values for the same gauge number, so check the material setting before you read the result.
How do I convert mm to gauge?
Choose Thickness to gauge, then type your thickness in mm. The tool gives the nearest gauge, the difference from that gauge, and the next nearest gauge. For example, 1.5 mm steel is closest to 16 ga (1.519 mm, 1.3% thicker), with 17 ga (1.367 mm) as the next nearest.
Can I use these numbers for a final design?
The results are for estimation. Check critical designs against the applicable standard and the data from your material supplier.
Related tools
- Stainless steel gauge chart — Use it when you need exact fractional thicknesses for stainless sheet.
- Aluminum gauge chart — Use it when your sheet is aluminum and uses the Brown & Sharpe gauge.
- Galvanized steel gauge chart — Use it when your sheet has a zinc coating and needs the galvanized thickness.
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