Sheet Metal Gauge Converter
Convert sheet metal gauge numbers to thickness in millimeters and inches for steel, aluminum, stainless steel, and galvanized steel.
Select a gauge number and metal type to see the thickness in mm and inches.
Understanding Sheet Metal Gauge
Sheet metal gauge is a numbering system used to indicate the thickness of metal sheets. The system originated in the wire industry in the 1800s and has been adopted for sheet metal. Counterintuitively, a higher gauge number means a thinner sheet. For example, 10-gauge steel is much thicker than 22-gauge steel. This is because the gauge number originally referred to how many times the metal was drawn through a reducing die.
Important: Gauge thickness varies by metal type. A 16-gauge steel sheet is NOT the same thickness as 16-gauge aluminum. Always use the correct gauge table for your specific metal.
Standard Steel (Manufacturers Standard Gauge):
| Gauge | Inches | mm |
|---|---|---|
| 7 | 0.1793 | 4.554 |
| 8 | 0.1644 | 4.176 |
| 10 | 0.1345 | 3.416 |
| 11 | 0.1196 | 3.038 |
| 12 | 0.1046 | 2.657 |
| 14 | 0.0747 | 1.897 |
| 16 | 0.0598 | 1.519 |
| 18 | 0.0478 | 1.214 |
| 20 | 0.0359 | 0.912 |
| 22 | 0.0299 | 0.759 |
| 24 | 0.0239 | 0.607 |
| 26 | 0.0179 | 0.455 |
| 28 | 0.0149 | 0.378 |
| 30 | 0.0120 | 0.305 |
Aluminum (Brown and Sharpe / AWG):
Aluminum uses the Brown and Sharpe (American Wire Gauge) system, which gives different thicknesses for the same gauge number. For instance, 16-gauge aluminum is 0.0508 inches (1.291 mm), while 16-gauge steel is 0.0598 inches (1.519 mm).
Galvanized Steel:
Galvanized steel gauges account for the zinc coating layer, so the base metal thickness is slightly less than standard steel of the same gauge. The total thickness including the coating remains close to the nominal gauge value.
Practical Tips:
- HVAC ductwork typically uses 22-26 gauge galvanized steel
- Car body panels are usually 18-20 gauge steel
- Roofing panels are commonly 24-26 gauge
- Heavy structural work uses 7-11 gauge
- When ordering from suppliers, always specify the metal type alongside the gauge number to avoid costly errors