12 Gauge Steel Thickness
12 gauge steel is 0.1046 inch (2.66 mm) thick, a little under 7/64 inch, and weighs about 4.37 pounds per square foot. 12 gauge stainless is 0.1094 in, galvanized 0.1084 in and aluminum 0.0808 in.
Gauge to thickness
Source: Manufacturers' Standard Gauge for sheet steel (41.82 lb per square foot per inch of thickness) · All sources
Thickness to nearest gauge
12 gauge is one of the heavier sheet thicknesses in everyday use. The tools below start on 12 gauge; switch the material, or measure a sheet to check its gauge.
12 gauge thickness by material
The same gauge number means a different thickness in each material, because each uses its own gauge system.
| Material | Inches | mm | Nearest fraction | lb/ft² |
|---|---|---|---|---|
| Steel | 0.1046 | 2.66 | 7/64 in | 4.374 |
| Galvanized steel | 0.1084 | 2.75 | 7/64 in | — |
| Stainless steel | 0.1094 | 2.78 | 7/64 in | — |
| Aluminum | 0.0808 | 2.05 | 5/64 in | — |
12 gauge compared with nearby gauges
| Gauge | Steel | Galvanized steel | Stainless steel | Aluminum |
|---|---|---|---|---|
| 10 ga | 0.1345 in3.42 mm | 0.1382 in3.51 mm | 0.1406 in3.57 mm | 0.1019 in2.59 mm |
| 11 ga | 0.1196 in3.04 mm | 0.1233 in3.13 mm | 0.1250 in3.18 mm | 0.0907 in2.30 mm |
| 12 ga | 0.1046 in2.66 mm | 0.1084 in2.75 mm | 0.1094 in2.78 mm | 0.0808 in2.05 mm |
| 13 ga | 0.0897 in2.28 mm | 0.0934 in2.37 mm | 0.0938 in2.38 mm | 0.0720 in1.83 mm |
| 14 ga | 0.0747 in1.90 mm | 0.0785 in1.99 mm | 0.0781 in1.98 mm | 0.0641 in1.63 mm |
The full range from 3 to 30 gauge is on the sheet metal gauge chart.
Working with 12 gauge steel
- Cutting: too thick for hand snips. Use a plasma cutter, an abrasive or cold-cut saw, or a shear rated for 12 gauge.
- Bending: a press brake or heavy bending brake. Small hand brakes are often rated only to 16 or 18 gauge mild steel, so check the rating before you try.
- Welding: MIG, stick and TIG all work well at this thickness.
Actual sheet thickness varies within the tolerances in ASTM A568. If a part must fit closely, measure the sheet with calipers or a micrometer rather than relying on the gauge number.
12 gauge steel, 0.1046 in, is a little under 7/64 inch (0.1094 in).
Weight of a 12 gauge steel sheet
At 4.37 lb per square foot, common sheet sizes weigh about:
- 2 × 4 ft (8 sq ft): 35 lb
- 4 × 4 ft (16 sq ft): 70 lb
- 4 × 8 ft (32 sq ft): 140 lb
- 4 × 10 ft (40 sq ft): 175 lb
Frequently asked questions
How thick is 12 gauge steel in mm?
2.66 mm (0.1046 inch × 25.4).
How thick is 12 gauge steel in inches?
0.1046 inch, just under 7/64 inch (0.109 in) and a little over 3/32 inch (0.094 in).
How much does 12 gauge steel weigh?
About 4.37 pounds per square foot (21.4 kg/m²). A 4 × 8 ft sheet weighs about 140 lb.
Is 12 gauge thicker than 14 gauge?
Yes. Lower gauge numbers are thicker: 12 gauge steel is 0.1046 in and 14 gauge is 0.0747 in, about 40% thicker.
Is 12 gauge stainless the same thickness as 12 gauge steel?
No. 12 gauge stainless is 0.1094 in (2.78 mm), about 5% thicker than 12 gauge carbon steel, and 12 gauge aluminum is much thinner at 0.0808 in (2.05 mm).
What is 12 gauge steel used for?
Brackets, frames, equipment guards, trailer and truck parts, heavy enclosures and shelving. It is thick enough to be structural in small parts but can still be cut and bent in a typical fabrication shop.
Sources
- Manufacturers' Standard Gauge for sheet steel (41.82 lb per square foot per inch of thickness)
- ASTM A568/A568M: thickness tolerances for carbon steel sheet
- Aluminum sheet: Brown & Sharpe (AWG) gauge series; stainless and galvanized gauges as published by mills
Page record
- Sources
- 3 cited, listed above
- Tested
- 15 automated checks of this converter run in a real browser before every release
- Last updated
- November 14, 2026
- Corrections
- Report an error on the contact page; fixes are logged in sources and methodology
Related charts and converters
- Sheet Metal GaugeGauge to inches and mm for steel, galvanized, stainless and aluminum.
- Wire Gauge ChartAWG sizes 4/0 to 40 with diameter, resistance and amp ratings.
- Linear MeasureInches to leagues: the US and traditional length units, with exact metric values.