Sheet Metal Gauge Chart
Unlike standard wire gauge, sheet metal gauges vary depending on the material. A 16-gauge steel sheet is not the same thickness as a 16-gauge aluminum sheet. Always specify the decimal inch or millimeter thickness in mechanical drawings.
| Gauge (Ga) | Standard Steel (in) | Galvanized Steel (in) | Stainless Steel (in) | Aluminum (in) | Avg. Metric (mm) |
|---|---|---|---|---|---|
| 10 | 0.1345" | 0.1382" | 0.1406" | 0.1019" | 3.41 |
| 11 | 0.1196" | 0.1233" | 0.1250" | 0.0907" | 3.04 |
| 12 | 0.1046" | 0.1084" | 0.1094" | 0.0808" | 2.66 |
| 14 | 0.0747" | 0.0785" | 0.0781" | 0.0641" | 1.90 |
| 16 | 0.0598" | 0.0635" | 0.0625" | 0.0508" | 1.52 |
| 18 | 0.0478" | 0.0516" | 0.0500" | 0.0403" | 1.21 |
| 20 | 0.0359" | 0.0396" | 0.0375" | 0.0320" | 0.91 |
| 22 | 0.0299" | 0.0336" | 0.0312" | 0.0253" | 0.76 |
| 24 | 0.0239" | 0.0276" | 0.0250" | 0.0201" | 0.61 |
⚠️ Engineering Warning: Why do Galvanized sizes differ?
Galvanized steel is essentially Standard Steel that has been dipped in zinc. The gauge number applies to the base steel before coating. The zinc coating adds approximately 0.0037" to the total thickness.
Additionally, Aluminum uses the Brown & Sharpe (AWG) gauge system, whereas Steel uses the Manufacturer's Standard Gauge (MSG). This is why a 14 Ga Aluminum sheet is significantly thinner than a 14 Ga Steel sheet.