8 gauge steel thickness
8 gauge steel is 0.1644 in (4.18 mm) thick, per the Manufacturers' Standard Gauge. The same gauge number means a different thickness in other metals: aluminium 0.1285 in.
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| Material | Gauge standard | Thickness (in) | Thickness (mm) | kg/m² |
|---|---|---|---|---|
| Steel (this page) | Manufacturers' Standard Gauge | 0.1644 | 4.18 | 32.78 |
| Aluminium | Brown & Sharpe (AWG) gauge | 0.1285 | 3.26 | 8.75 |
| Gauge | Thickness (in) | Thickness (mm) | kg/m² | lb/ft² |
|---|---|---|---|---|
| 7 ga | 0.1793 | 4.55 | 35.75 | 7.32 |
| 8 ga (this page) | 0.1644 | 4.18 | 32.78 | 6.71 |
| 10 ga | 0.1345 | 3.42 | 26.82 | 5.49 |
| 11 ga | 0.1196 | 3.04 | 23.85 | 4.88 |
| 12 ga | 0.1046 | 2.66 | 20.86 | 4.27 |
| 14 ga | 0.0747 | 1.90 | 14.89 | 3.05 |
| 16 ga | 0.0598 | 1.52 | 11.92 | 2.44 |
Practical notes
Gauge is a convention, not a unit: a higher gauge number is thinner, and steps are not even. 8 gauge is 0.1644 in for uncoated carbon steel (cold-rolled / hot-rolled sheet), but aluminium 0.1285 in. Put the decimal thickness on drawings and purchase orders to avoid mix-ups.
Mills supply sheet to a thickness tolerance (ASTM A568 / A480 / EN 10131), so a measured sheet can be a few thousandths of an inch off the nominal value. Measure with a micrometer before calculating bend allowances or press-fit clearances.
Weight per area here is thickness × density (carbon steel, 7.85 g/cm³): 4.18 mm × 7.85 = 32.78 kg/m². Multiply by the sheet area for blank weight; a 4 × 8 ft sheet is 2.973 m², so about 97.5 kg (214.8 lb).
Manufacturers' Standard Gauge is based on a steel weight of 41.82 lb/ft² per inch of thickness, which is why its decimal values look irregular.
FAQ
How thick is 8 gauge steel?
0.1644 in, which is 4.18 mm, per the Manufacturers' Standard Gauge.
How thick is 8 gauge in mm?
For steel, 8 gauge is 4.18 mm. In other metals: aluminium 3.26 mm.
How much does 8 gauge steel weigh?
About 32.78 kg per square metre (6.71 lb per square foot), using carbon steel, 7.85 g/cm³.
Is 8 gauge thicker than 7 gauge?
No. Higher gauge numbers are thinner: 7 ga steel is 0.1793 in, 8 ga is 0.1644 in.
Sources: Steel: Manufacturers' Standard Gauge · Densities: EN 10025 / ASTM A1008 (steel), ASTM A240 (stainless), Aluminum Association (5052) · 1 in = 25.4 mm (exact)
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