BenchReference

Sheet Metal Gauge Sizes

Gauge thickness by material — and the trap: the same gauge number is a different thickness in each material. 16 gauge is 0.0598″ in steel, 0.0635″ galvanized, 0.0625″ stainless, and 0.0508″ in aluminum. Steel uses the Manufacturers' Standard Gauge; aluminum follows B&S, which is the same scale as wire gauge (AWG).

Identify a gauge from a measured thickness

Decimal inches by default; add “mm” for millimeters. Measure with a caliper or micrometer away from sheared edges — the shear burr reads thick. Try:

Gauge chart (inches)

Gauge Steel (MSG) Galvanized Stainless Aluminum
3 0.2391 — 0.2500 0.2294
4 0.2242 — 0.2344 0.2043
5 0.2092 — 0.2187 0.1819
6 0.1943 — 0.2031 0.1620
7 0.1793 — 0.1875 0.1443
8 0.1644 0.1681 0.1719 0.1285
9 0.1495 0.1532 0.1562 0.1144
10 0.1345 0.1382 0.1406 0.1019
11 0.1196 0.1233 0.1250 0.0907
12 0.1046 0.1084 0.1094 0.0808
13 0.0897 0.0934 0.0937 0.0720
14 0.0747 0.0785 0.0781 0.0641
15 0.0673 0.0710 0.0703 0.0571
16 0.0598 0.0635 0.0625 0.0508
17 0.0538 0.0575 0.0562 0.0453
18 0.0478 0.0516 0.0500 0.0403
19 0.0418 0.0456 0.0437 0.0359
20 0.0359 0.0396 0.0375 0.0320
21 0.0329 0.0366 0.0344 0.0285
22 0.0299 0.0336 0.0312 0.0253
23 0.0269 0.0306 0.0281 0.0226
24 0.0239 0.0276 0.0250 0.0201
25 0.0209 0.0247 0.0219 0.0179
26 0.0179 0.0217 0.0187 0.0159
27 0.0164 0.0202 0.0172 0.0142
28 0.0149 0.0187 0.0156 0.0126
29 0.0135 0.0172 0.0141 0.0113
30 0.0120 0.0157 0.0125 0.0100

“—” = that material's table doesn't publish the gauge. Steel is the Manufacturers' Standard Gauge (not the older 1893 US Standard Gauge, whose values differ); galvanized includes the coating; stainless follows the conventional supplier table — no single standard governs it.

Data provenance. Sheet-metal gauge tables: Manufacturers’ Standard Gauge (steel), galvanized, and stainless (Industry reference). ASTM B258, Standard Specification for Nominal Diameters of AWG Sizes (ASTM International). Gauge is a legacy sizing convention — specify decimal thickness on drawings. Actual sheets carry rolling tolerances. See all data sources.