A sheet metal gauge is an old-school way of naming thickness where a higher number means a thinner sheet. Because it is a numbering system and not a real unit, each metal has its own chart. Use the tables below to convert gauge to an exact decimal thickness.
Gauge to thickness chart (decimal inches)
| Gauge | Steel | Stainless | Aluminum |
|---|---|---|---|
| 7 ga | 0.1793" | 0.1875" | 0.1443" |
| 8 ga | 0.1644" | 0.1719" | 0.1285" |
| 10 ga | 0.1345" | 0.1406" | 0.1019" |
| 11 ga | 0.1196" | 0.1250" | 0.0907" |
| 12 ga | 0.1046" | 0.1094" | 0.0808" |
| 14 ga | 0.0747" | 0.0781" | 0.0641" |
| 16 ga | 0.0598" | 0.0625" | 0.0508" |
| 18 ga | 0.0478" | 0.0500" | 0.0403" |
| 20 ga | 0.0359" | 0.0375" | 0.0320" |
| 22 ga | 0.0299" | 0.0313" | 0.0253" |
| 24 ga | 0.0239" | 0.0250" | 0.0201" |
Steel uses the Manufacturers' Standard Gauge, stainless uses the stainless steel gauge, and aluminum uses the Brown & Sharpe gauge. Values are nominal and rounded.
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- Smaller gauge equals thicker metal. 12 gauge is thicker than 20 gauge.
- Match the column to your metal. A 16 gauge label means 0.0598 inch in steel but 0.0508 inch in aluminum. They are not the same.
- When precision matters, use the decimal. Give us the exact thickness in inches or mm and there is no ambiguity.
Why steel and aluminum differ
The gauge systems come from different industries and different eras. Steel gauge was originally based on weight per square foot, while aluminum uses the Brown & Sharpe system from the wire and metal trades. Nobody standardized them together, so the numbers never lined up. That history is why a spec that only says "16 gauge" without naming the metal is incomplete.
Which thickness should you use
Thickness drives strength, weight, cost, and how the part bends. A quick rule of thumb:
- Light duty18 to 22 gauge for covers, shields, and light brackets.
- General use11 to 16 gauge for most enclosures and brackets.
- Structural7 to 10 gauge or plate for load-bearing parts.
Thicker is stronger but heavier and more expensive, and it needs a larger bend radius. If you are unsure, our design guide walks through the tradeoffs.
Inches to millimeters
To convert any thickness in the chart to millimeters, multiply by 25.4. For example, 16 gauge steel at 0.0598 inch is about 1.52 mm. Darioo accepts either unit, so use whichever your CAD tool is set to.
Skip the lookup: if you send a 3D model or a DXF, we read the thickness directly from your file and match it to stocked material. No gauge guessing required.