Sheet Metal Gauge Chart

Higher gauge numbers are thinner. 16 gauge steel is 0.0598 in (1.52 mm), 14 gauge is 0.0747 in (1.90 mm) and 12 gauge is 0.1046 in (2.66 mm). The same gauge is a different thickness in stainless or aluminum.

Gauge to thickness

Source: ASTM A568/A568M: Standard specification for steel, sheet, carbon, structural, and high-strength, low-alloy (thickness tolerances) · All sources

Thickness to nearest gauge

Look up a gauge for any of the four common sheet materials, or measure a sheet and find its nearest gauge. The full chart is below and prints on one page.

Sheet metal gauge chart

Nominal thickness for each gauge. Steel weight is for uncoated carbon steel. "—" means the gauge isn't commonly made in that material.

Sheet metal gauge thickness by material
Gauge	Steel		Galvanized steel		Stainless steel		Aluminum		Steel lb/ft²
Gauge	in	mm	in	mm	in	mm	in	mm	Steel lb/ft²
3	0.2391	6.07	—	—	—	—	—	—	9.999
4	0.2242	5.69	—	—	—	—	—	—	9.376
5	0.2092	5.31	—	—	—	—	—	—	8.749
6	0.1943	4.94	—	—	—	—	0.1620	4.11	8.126
7	0.1793	4.55	—	—	0.1875	4.76	0.1443	3.67	7.498
8	0.1644	4.18	0.1681	4.27	0.1719	4.37	0.1285	3.26	6.875
9	0.1495	3.80	0.1532	3.89	0.1563	3.97	0.1144	2.91	6.252
10	0.1345	3.42	0.1382	3.51	0.1406	3.57	0.1019	2.59	5.625
11	0.1196	3.04	0.1233	3.13	0.1250	3.18	0.0907	2.30	5.002
12	0.1046	2.66	0.1084	2.75	0.1094	2.78	0.0808	2.05	4.374
13	0.0897	2.28	0.0934	2.37	0.0938	2.38	0.0720	1.83	3.751
14	0.0747	1.90	0.0785	1.99	0.0781	1.98	0.0641	1.63	3.124
15	0.0673	1.71	0.0710	1.80	0.0703	1.79	0.0571	1.45	2.814
16	0.0598	1.52	0.0635	1.61	0.0625	1.59	0.0508	1.29	2.501
17	0.0538	1.37	0.0575	1.46	0.0563	1.43	0.0453	1.15	2.250
18	0.0478	1.21	0.0516	1.31	0.0500	1.27	0.0403	1.02	1.999
19	0.0418	1.06	0.0456	1.16	0.0438	1.11	0.0359	0.91	1.748
20	0.0359	0.91	0.0396	1.01	0.0375	0.95	0.0320	0.81	1.501
21	0.0329	0.84	0.0366	0.93	0.0344	0.87	0.0285	0.72	1.376
22	0.0299	0.76	0.0336	0.85	0.0313	0.80	0.0253	0.64	1.250
23	0.0269	0.68	0.0306	0.78	0.0281	0.71	0.0226	0.57	1.125
24	0.0239	0.61	0.0276	0.70	0.0250	0.64	0.0201	0.51	0.999
25	0.0209	0.53	0.0247	0.63	0.0219	0.56	0.0179	0.45	0.874
26	0.0179	0.45	0.0217	0.55	0.0188	0.48	0.0159	0.40	0.749
27	0.0164	0.42	0.0202	0.51	0.0172	0.44	0.0142	0.36	0.686
28	0.0149	0.38	0.0187	0.47	0.0156	0.40	0.0126	0.32	0.623
29	0.0135	0.34	0.0172	0.44	0.0141	0.36	0.0113	0.29	0.565
30	0.0120	0.30	0.0157	0.40	0.0125	0.32	0.0100	0.25	0.502

Reading a gauge number

A gauge is a size number, not a unit of length, and it runs backwards: 10 gauge is heavy plate-like sheet, 30 gauge is thin enough to cut with scissors. Each step is not a fixed amount. Between 10 and 11 gauge steel the difference is 0.0149 in; between 28 and 29 it's 0.0014 in.

The US steel gauge is the Manufacturers' Standard Gauge. It started as a weight system: each gauge is a weight per square foot, and the thickness is that weight divided by steel's 41.82 lb per square foot per inch. So 10 gauge steel is 5.625 lb/ft² and 0.1345 in thick.

Measuring a sheet

Use calipers or a micrometer away from the cut edge, where burrs and rollover can add thickness.
Paint, powder coat and galvanizing add to the reading. Galvanized gauges already include a standard zinc coating.
Real sheets vary. ASTM A568 allows a mill tolerance of a few thousandths of an inch either side of nominal, so a reading between two gauges is normal. The tool above flags readings more than 10% from any gauge.

Typical uses by gauge

Common applications (steel)
Gauge	Typical uses
7–10	Trailer beds, heavy brackets, machine guards, structural plates
11–14	Truck and trailer bodies, heavy enclosures, shelving uprights, welding projects
16–18	Car body panels and patch panels, tool boxes, electrical enclosures, stud framing
20–24	HVAC ductwork, appliance housings, commercial roofing and siding
26–30	Residential roofing and siding panels, flashing, light duct and trim

Frequently asked questions

How thick is 16 gauge steel?

0.0598 inch, or 1.52 mm. 16 gauge galvanized steel is slightly thicker (0.0635 in) because of the zinc coating, 16 gauge stainless is 0.0625 in and 16 gauge aluminum is 0.0508 in.

How thick is 12 gauge steel?

0.1046 inch, or 2.66 mm. Uncoated, it weighs about 4.37 pounds per square foot.

Is 14 gauge thicker than 16 gauge?

Yes. Gauge numbers run backwards: the lower the number, the thicker the sheet. 14 gauge steel is 0.0747 in; 16 gauge is 0.0598 in.

Why are steel and aluminum gauges different?

Gauges grew out of different trade systems. Steel gauge was originally defined by weight per square foot, so the thickness depends on steel's density. Aluminum uses the Brown & Sharpe (wire gauge) series. Because of the confusion, aluminum is often ordered by decimal thickness instead.

What gauge is metal roofing?

Residential steel roofing panels are commonly 26 or 29 gauge; 24 and 22 gauge are heavier commercial grades. Standing-seam roofs are often 24 gauge.

Is sheet metal gauge the same as wire gauge?

No. Wire uses American Wire Gauge (AWG) for diameter, and 16 AWG wire is 0.0508 in across, which happens to match 16 gauge aluminum sheet but not steel. Always check which gauge system a number refers to.

Sources

ASTM A568/A568M: Standard specification for steel, sheet, carbon, structural, and high-strength, low-alloy (thickness tolerances)
Manufacturers' Standard Gauge for sheet steel (41.82 lb per square foot per inch of thickness)
Aluminum: Brown & Sharpe (AWG) series per ASTM B258

Page record

Sources: 3 cited, listed above
Tested: 14 automated checks of this converter run in a real browser before every release
Last updated: November 5, 2026
Corrections: Report an error on the contact page; fixes are logged in sources and methodology

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