What is Sheet Metal Gauge?
Sheet metal thickness in the US is specified by gauge number rather than direct measurements. Confusingly, the gauge-to-thickness relationship is different for different metals. A 16-gauge sheet of steel is not the same thickness as 16-gauge aluminum.
The tables below give you the actual thickness in inches and millimeters for the most common gauge systems.
Steel Sheet Metal Gauge (USS / Manufacturer’s Standard)
| Gauge | Thickness (in) | Thickness (mm) | Weight (lb/ft²) |
|---|---|---|---|
| 7 | 0.1793 | 4.554 | 7.500 |
| 8 | 0.1644 | 4.176 | 6.875 |
| 9 | 0.1495 | 3.797 | 6.250 |
| 10 | 0.1345 | 3.416 | 5.625 |
| 11 | 0.1196 | 3.038 | 5.000 |
| 12 | 0.1046 | 2.657 | 4.375 |
| 13 | 0.0897 | 2.278 | 3.750 |
| 14 | 0.0747 | 1.897 | 3.125 |
| 15 | 0.0673 | 1.709 | 2.813 |
| 16 | 0.0598 | 1.519 | 2.500 |
| 17 | 0.0538 | 1.367 | 2.250 |
| 18 | 0.0478 | 1.214 | 2.000 |
| 19 | 0.0418 | 1.062 | 1.750 |
| 20 | 0.0359 | 0.912 | 1.500 |
| 22 | 0.0299 | 0.759 | 1.250 |
| 24 | 0.0239 | 0.607 | 1.000 |
| 26 | 0.0179 | 0.455 | 0.750 |
| 28 | 0.0149 | 0.378 | 0.625 |
| 30 | 0.0120 | 0.305 | 0.500 |
Stainless Steel Gauge
Stainless steel uses a different gauge system than carbon steel. Don’t mix them up — a call for “16 gauge stainless” is thinner than “16 gauge steel.”
| Gauge | Thickness (in) | Thickness (mm) |
|---|---|---|
| 8 | 0.17187 | 4.366 |
| 10 | 0.14062 | 3.572 |
| 11 | 0.12500 | 3.175 |
| 12 | 0.10937 | 2.778 |
| 14 | 0.07812 | 1.984 |
| 16 | 0.06250 | 1.588 |
| 18 | 0.05000 | 1.270 |
| 20 | 0.03750 | 0.953 |
| 22 | 0.03125 | 0.794 |
| 24 | 0.02500 | 0.635 |
| 26 | 0.01875 | 0.476 |
| 28 | 0.01562 | 0.397 |
| 30 | 0.01250 | 0.318 |
Aluminum Sheet Gauge (Brown & Sharpe / AWG)
| Gauge | Thickness (in) | Thickness (mm) |
|---|---|---|
| 8 | 0.1285 | 3.264 |
| 10 | 0.1019 | 2.588 |
| 12 | 0.0808 | 2.052 |
| 14 | 0.0641 | 1.628 |
| 16 | 0.0508 | 1.290 |
| 18 | 0.0403 | 1.024 |
| 20 | 0.0320 | 0.813 |
| 22 | 0.0253 | 0.643 |
| 24 | 0.0201 | 0.511 |
| 26 | 0.0159 | 0.404 |
Key Takeaway
Always specify thickness in inches or mm on your drawings — not gauge. Gauge numbers vary by material and can cause costly mistakes. Use gauge in conversation and purchasing, but put the actual dimension on the print.
Related: Drill Size Chart | Surface Finish Guide