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Sheet Metal Gauge Chart
US standard gauge numbers converted to thickness in inches and millimetres. Lower gauge number means thicker metal.
| Gauge | Thickness (in) | Thickness (mm) |
|---|
Standard: US Standard Gauge (manufacturer) · Data checked: 2026-10-14
Frequently asked questions
Why is 16 gauge not one thickness everywhere?
Because 'gauge' is not one standard. The US Standard Gauge applies to iron and steel sheet and plate; galvanised sheet has its own manufacturer tables; aluminium and stainless have others again. Two suppliers quoting 16 gauge in different materials can be 0.5 mm apart.
Which way do the numbers run?
Bigger number, thinner sheet. 7 gauge is heavy plate-like stock around 4.8 mm and 30 gauge is shim stock around 0.3 mm.
What is the difference between sheet, plate and strip?
Thickness mostly. Steel is generally called sheet below about 6 mm and plate above; strip is narrow and often supplied coiled. The boundary is a convention, not a standard, so cut-offs vary between suppliers.
Does the gauge number tell me the weight?
Not directly, but weight per square metre is a straightforward calculation once you have the thickness: thickness in metres times 7850 kg per cubic metre for steel. That is the figure purchasing usually wants.