12 gauge steel thickness
12 gauge sheet steel is 0.1046 inches thick, or 2.66 mm. It weighs 4.27 lb per square foot, so a standard 4×8 sheet comes in around 137 lb.
Inches
0.1046"
Millimetres
2.66 mm
Weight
4.27 lb/ft²
4×8 sheet
137 lb
What 12 gauge is used for
Structural framing accessories, heavy brackets, and mezzanine components. The usual step up when 14 gauge flexes too much.
12 gauge in other materials
Sheet steel
0.1046"
Galvanized
0.1084"
Stainless
0.1094"
Galvanized and stainless use their own gauge series — the same gauge number is a different thickness in each. Reading a galvanized order off a plain steel chart is one of the most common ordering mistakes in the shop.
Next gauge up and down
Thicker — 11 gauge
0.1196"
14% thicker than 12 gauge
Thinner — 13 gauge
0.0897"
14% thinner than 12 gauge
Calculate a 12 gauge order
Gauge converter
Inches
0.1046"
Millimetres
2.66 mm
Weight
4.27 lb/ft²
Total
427 lb
Weight is calculated at 40.84 lb/ft² per inch of thickness. The Manufacturers' Standard Gauge quotes a nominal 4.37 lb/ft² for 12 gauge, based on a historical wrought-iron density — if a mill cert and your calculation disagree slightly, that is usually why.
Full gauge chart
| Gauge | Steel (in) | Steel (mm) | lb/ft² | Galvanized (in) | Stainless (in) |
|---|---|---|---|---|---|
| 3 ga | 0.2391 | 6.07 | 9.76 | — | 0.2500 |
| 4 ga | 0.2242 | 5.69 | 9.16 | — | 0.2344 |
| 5 ga | 0.2092 | 5.31 | 8.54 | — | 0.2187 |
| 6 ga | 0.1943 | 4.94 | 7.94 | — | 0.2031 |
| 7 ga | 0.1793 | 4.55 | 7.32 | — | 0.1875 |
| 8 ga | 0.1644 | 4.18 | 6.71 | 0.1681 | 0.1719 |
| 9 ga | 0.1495 | 3.80 | 6.11 | 0.1532 | 0.1562 |
| 10 ga | 0.1345 | 3.42 | 5.49 | 0.1382 | 0.1406 |
| 11 ga | 0.1196 | 3.04 | 4.88 | 0.1233 | 0.1250 |
| 12 ga | 0.1046 | 2.66 | 4.27 | 0.1084 | 0.1094 |
| 13 ga | 0.0897 | 2.28 | 3.66 | 0.0934 | 0.0937 |
| 14 ga | 0.0747 | 1.90 | 3.05 | 0.0785 | 0.0781 |
| 15 ga | 0.0673 | 1.71 | 2.75 | 0.0710 | 0.0703 |
| 16 ga | 0.0598 | 1.52 | 2.44 | 0.0635 | 0.0625 |
| 17 ga | 0.0538 | 1.37 | 2.20 | 0.0575 | 0.0562 |
| 18 ga | 0.0478 | 1.21 | 1.95 | 0.0516 | 0.0500 |
| 19 ga | 0.0418 | 1.06 | 1.71 | 0.0456 | 0.0437 |
| 20 ga | 0.0359 | 0.91 | 1.47 | 0.0396 | 0.0375 |
| 21 ga | 0.0329 | 0.84 | 1.34 | 0.0366 | 0.0344 |
| 22 ga | 0.0299 | 0.76 | 1.22 | 0.0336 | 0.0312 |
| 23 ga | 0.0269 | 0.68 | 1.10 | 0.0306 | 0.0281 |
| 24 ga | 0.0239 | 0.61 | 0.98 | 0.0276 | 0.0250 |
| 25 ga | 0.0209 | 0.53 | 0.85 | 0.0247 | 0.0219 |
| 26 ga | 0.0179 | 0.45 | 0.73 | 0.0217 | 0.0187 |
| 27 ga | 0.0164 | 0.42 | 0.67 | 0.0202 | 0.0172 |
| 28 ga | 0.0149 | 0.38 | 0.61 | 0.0187 | 0.0156 |