Sheet Metal: Gauges, Metals and Cuts

Sheet metal comes in steel, galvanized, stainless and aluminum. Gauge numbers differ by metal.

Updated Nov 1, 2026. Edited by: Ilyass Ben Hakim.

Where to buy

Hardware stores stock small sheets for repairs. Metal supply yards sell full sheets and often shear them to size. Online metal shops ship cut pieces to your door.

Professional insight

Fabricators order sheet by decimal thickness and alloy. Gauge alone means different sizes for different metals.

Ask for thickness in inches or mm, not gauge.
Galvanized runs slightly thicker than bare steel of equal gauge.
Specify alloy and temper for aluminum, such as 5052-H32.
Order shear cuts with a little bend allowance added.

Check the label

Metal type: cold rolled, galvanized, stainless or aluminum.
Thickness in inches or mm, not only gauge.
Alloy or grade, such as 304 stainless or 6061 aluminum.
Sheet length and width, and cut tolerance.
Finish: mill, brushed, perforated or diamond plate.
Protective film on one or both sides.
Heat or mill certificate if the job needs one.

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Specs to match

Nominal thickness by gauge, in inches
Gauge	Steel	Galvanized	Aluminum	Stainless
10	0.135	0.138	0.102	0.141
14	0.075	0.079	0.064	0.078
16	0.060	0.064	0.051	0.063
18	0.048	0.052	0.040	0.050
20	0.036	0.040	0.032	0.038
22	0.030	0.034	0.025	0.031

Higher gauge numbers mean thinner sheet. Confirm the exact figure on your supplier's chart, since values vary slightly.

Types

Cold rolled steel

Smooth and easy to weld. Rusts unless painted or coated.

Galvanized steel

Zinc coated for outdoor use, ducts and flashing.

Stainless steel

Resists corrosion. Common in kitchens and food equipment.

Aluminum

Light and rust free. Softer and harder to weld well.

Copper and brass

Used for roofing details, art and decor.

Sheet metal weight estimate

Steel sheet weight

Calculator

Uses about 40.8 lb per square foot per inch of steel thickness.

Length

Width

Thickness

Approximate weight19.58 lb

Safe use

Ways to save

Ask supply yards for drops and offcuts.
Buy full sheets when you need several parts.
Pick up locally to avoid oversize freight charges.
Choose mill finish when looks do not matter.

Common questions

Is 16 gauge thicker than 20 gauge?: Yes. Lower gauge numbers are thicker sheet.
Can a store cut sheet metal for me?: Many metal suppliers shear sheets to size. Most hardware stores sell fixed sizes only.
Which metal is best outdoors?: Galvanized steel, stainless or aluminum. Bare steel needs paint to resist rust.