Sheet Metal Gauge Chart & Converter
Gauge to mm by metal type.
Gauge to mm by metal type.
How to use Sheet Metal Gauge Chart & Converter
- Choose your metal: steel, galvanised, stainless, or aluminium
- Select a gauge, or enter a thickness to find the nearest gauge
- Read the exact thickness in millimetres and inches for that metal
About Sheet Metal Gauge Chart & Converter
This sheet metal gauge chart turns a gauge number into an exact thickness in both millimetres and inches, correctly for each metal. Pick steel, galvanised, stainless or aluminium, choose a gauge and read off the figure — or type a thickness in to find the nearest gauge for that metal. Because gauge is not a universal measurement, one generic chart is the wrong tool: the same number means different things depending on what you are cutting, so the first thing you do is tell it the metal, and every figure after that is specific to that material.
16 gauge is about 1.52 mm in steel but only 1.29 mm in aluminium, so a steel gauge chart and an aluminium gauge chart genuinely disagree — and stainless and galvanised each sit at their own values again. That is the whole point of this: a steel sheet metal gauge chart, a stainless steel chart, an aluminum chart and a galvanized chart in one place, so you convert gauge to thickness without guessing which scale applies. Whether you need a quick gauge-to-mm conversion, the full range of gauge sizes, or just to sanity-check a supplier's spec, the number matches the metal you selected.
It is completely free, needs no sign-up, and runs entirely in your browser — nothing you enter is uploaded anywhere.
Use it as a sheet metal gauge chart — gauge number to thickness in inches and millimetres — or convert a single gauge.
Frequently asked questions
- What is 16 gauge in millimetres?
- It depends on the metal: 16 gauge is about 1.52 mm in steel, 1.61 mm in galvanised steel, 1.59 mm in stainless, and 1.29 mm in aluminium. That's exactly why you have to pick the metal first.
- How do I convert sheet metal gauge to thickness?
- Choose the metal, then either pick a gauge number to see its thickness in millimetres and inches, or type a thickness to find the nearest gauge. There is no formula to memorise and no separate table to cross-reference — the conversion updates as you change the metal.
- What is the standard steel sheet metal gauge chart?
- In the Manufacturers' Standard Gauge for steel, common sizes run roughly 10 ga ≈ 3.42 mm, 14 ga ≈ 1.90 mm, 16 ga ≈ 1.52 mm, 18 ga ≈ 1.21 mm and 20 ga ≈ 0.91 mm. Select steel in the tool and it lists the exact thickness for any gauge you pick.
- What is the gauge chart for stainless steel?
- Stainless has its own values that sit between plain steel and galvanised — for example 16 ga is about 1.59 mm, 18 ga about 1.27 mm and 20 ga about 0.95 mm. Choose stainless so you don't accidentally read plain-steel numbers, which are thinner at the same gauge.
- What is the aluminum sheet metal gauge chart?
- Aluminium uses the AWG (Brown & Sharpe) scale, so its gauges are thinner than steel: 16 ga is about 1.29 mm, 14 ga about 1.63 mm and 18 ga about 1.02 mm. Pick aluminium and the tool switches to the correct scale automatically.
- Why does gauge thickness differ by metal?
- Steel, galvanised and stainless use the Manufacturers' Standard Gauge, while aluminium, brass and copper use the AWG (Brown & Sharpe) scale — two different systems that assign different thicknesses to the same gauge number.
- Does galvanising change the thickness?
- Yes — galvanised steel is the base steel plus a zinc coating, so a galvanised sheet of a given gauge is slightly thicker than plain steel of the same gauge. Pick galvanised to get that adjusted figure rather than the plain-steel one.
- Is a higher gauge number thicker or thinner?
- Thinner. The gauge scale runs backwards, so 30 gauge is much thinner than 10 gauge.
- What thicknesses do the common gauge sizes cover?
- Sheet metal gauges typically run from about 3 (thick plate) up to 30 or higher (thin sheet), and the tool covers the full range for each metal. Because the scale is inverted, a bigger gauge number always means a thinner sheet.
- What gauge is 1 mm steel sheet?
- About 20 gauge (0.0359 in ≈ 0.91 mm is 20 ga, so 1 mm sits between 19 and 20 gauge). Enter the thickness in the tool to get the nearest gauge for your metal.
- Does it show inches as well as millimetres?
- Yes. Every result is shown in both millimetres and inches, so you can work in whichever unit your drawing, supplier or machine uses without a second conversion step.
- Can I print this sheet metal gauge chart?
- This is a live converter rather than a static printable chart, so the quickest route is to look up the exact gauge and metal you need and read the figure on screen. You can still use your browser's print function on the page if you want a paper copy of what's shown.