Sheet Metal Gauge Chart

Sheet-metal gauges are a historical hold-over — different materials use different standards, so gauge #16 steel is not the same thickness as gauge #16 aluminum or copper. Always specify the material along with the gauge, or better, spec the actual thickness in mm / thousandths of an inch. Carbon / stainless / galvanized use the Manufacturers Standard Gauge; aluminum and copper use the Browne & Sharpe (same as AWG) scale.

Carbon steel / Stainless / Galvanized (Manufacturers Std)

Gauge	Carbon Steel (in)	mm	Stainless (in)	mm	Galvanized (in)	mm
3	0.2391	6.073	0.2500	6.350	—	—
4	0.2242	5.695	0.2344	5.954	—	—
5	0.2092	5.314	0.2187	5.555	—	—
6	0.1943	4.935	0.2031	5.159	—	—
7	0.1793	4.554	0.1875	4.762	—	—
8	0.1644	4.176	0.1719	4.366	0.1681	4.270
9	0.1495	3.797	0.1562	3.967	0.1532	3.891
10	0.1345	3.416	0.1406	3.571	0.1382	3.510
11	0.1196	3.038	0.1250	3.175	0.1233	3.132
12	0.1046	2.657	0.1094	2.779	0.1084	2.753
13	0.0897	2.278	0.0937	2.380	0.0934	2.372
14	0.0747	1.897	0.0781	1.984	0.0785	1.994
15	0.0673	1.709	0.0703	1.786	0.0710	1.803
16	0.0598	1.519	0.0625	1.588	0.0635	1.613
17	0.0538	1.367	0.0562	1.428	0.0575	1.461
18	0.0478	1.214	0.0500	1.270	0.0516	1.311
19	0.0418	1.062	0.0437	1.110	0.0456	1.158
20	0.0359	0.912	0.0375	0.953	0.0396	1.006
21	0.0329	0.836	0.0344	0.874	0.0366	0.930
22	0.0299	0.759	0.0312	0.793	0.0336	0.853
23	0.0269	0.683	0.0281	0.714	0.0306	0.777
24	0.0239	0.607	0.0250	0.635	0.0276	0.701
25	0.0209	0.531	0.0219	0.556	0.0247	0.627
26	0.0179	0.455	0.0187	0.476	0.0217	0.551
27	0.0164	0.417	0.0172	0.437	0.0202	0.513
28	0.0149	0.378	0.0156	0.397	0.0187	0.475
29	0.0135	0.343	0.0140	0.356	0.0172	0.437
30	0.0120	0.305	0.0125	0.317	0.0157	0.399

Aluminum (Browne & Sharpe / AWG) — same scale as copper

Gauge	Aluminum (in)	mm	Aluminum 5052 H32 UTS* (ksi)
3	0.2294	5.827	33
4	0.2043	5.189	33
5	0.1819	4.621	33
6	0.1620	4.115	33
7	0.1443	3.665	33
8	0.1285	3.264	33
9	0.1144	2.906	33
10	0.1019	2.588	33
11	0.0907	2.304	33
12	0.0808	2.052	33
13	0.0720	1.829	33
14	0.0641	1.628	33
15	0.0571	1.450	33
16	0.0508	1.290	33
17	0.0453	1.150	33
18	0.0403	1.024	33
19	0.0359	0.912	33
20	0.0320	0.813	33
22	0.0253	0.643	33
24	0.0201	0.511	33
26	0.0159	0.404	33
28	0.0126	0.320	33
30	0.0100	0.254	33

Zinc gauge (separate scale — used for roof flashing, battery cans)

Gauge	Thickness (in)	mm
8	0.0160	0.406
10	0.0200	0.508
12	0.0240	0.610
14	0.0280	0.711
16	0.0360	0.914
18	0.0400	1.016
20	0.0440	1.118
22	0.0500	1.270
24	0.0560	1.422

Usage notes

Galvanized steel is the carbon-steel gauge thickness plus a zinc coating (typically 0.0007 to 0.0015" per side for G30 / G60 / G90 rating).
Stainless steel sheets are thicker than same-gauge carbon by ~4% because the Manufacturers Standard is based on weight — stainless is denser.
Aluminum uses Browne & Sharpe (B&S) — not Manufacturers Standard. #16 aluminum = 0.051", not 0.060".
Modern spec sheets increasingly drop gauge numbers entirely in favor of decimal inch or millimeter thickness. Do the same in drawings — "1.5 mm steel" has exactly one meaning; "16 ga steel" has four.
For bending: use a k-factor of 0.33-0.40 for soft steel, 0.44 for aluminum, and add setback per your brake's tooling.
Common structural gauges: 14-ga (0.075") for auto body panels, 11-ga (0.120") for brackets and machine guards, 16-ga (0.060") for HVAC duct, 22-26 ga for interior trim.

Quick convert — mm ↔ gauge (carbon steel)

6 mm	≈ #3 (0.239")
4 mm	≈ #7 / #8 (0.160")
3 mm	≈ #11 (0.120")
2 mm	≈ #14 (0.075")
1.5 mm	≈ #16 (0.060")
1 mm	≈ #20 (0.036")
0.8 mm	≈ #22 (0.030")
0.5 mm	≈ #26 (0.018")

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