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Steel Sheet Metal Gauge Chart

Carbon steel is the metal the gauge system was built around. Its chart is the Manufacturers' Standard Gauge, governed by ASTM A568, and it is the only one of the four systems on this site that carries a weight column — because for steel, gauge is weight. If you are converting a number for mild steel, carbon steel, or a quote that just says "sheet metal" with no other metal named, this is almost always the chart you want.

The range runs from 7 gauge at 0.1793 inches — stiff, plate-like sheet — down to 30 gauge at 0.0120 inches, thin enough to flex in your hands. Most fabrication work lives between 10 and 22 gauge. The full table below gives every gauge in inches and millimetres with its weight in pounds per square foot.

Steel gauge thickness chart

How the steel gauge system works

The Manufacturers' Standard Gauge is defined by a single constant: one inch of steel thickness weighs 41.82 pounds per square foot. Multiply any thickness on this chart by 41.82 and you get its weight — 16 gauge, at 0.0598 inches, works out to 2.501 pounds per square foot, and a standard 4 by 8 foot sheet of it weighs about 80 pounds. That weight column is not decoration. It is how the system was originally specified, and it is still the fastest way to estimate shipping weight, load on a rack, or whether a panel will sag on its span.

Because the steps are slices of a weight scale rather than a geometric series, steel gauge steps are uneven in thickness: the jump from 10 to 11 gauge is 0.0149 inches, while the jump from 29 to 30 is only 0.0015 inches. Fine work at the thin end gets fine steps; heavy work at the thick end gets coarse ones.

Common steel gauges and what they are used for

Auto body and patch-panel work usually sits at 18 to 20 gauge — 0.0478 to 0.0359 inches — thick enough to weld and shape, thin enough to form by hand tools. General fabrication, brackets, and enclosures run 14 to 16 gauge. Trailer decks, hoppers, and anything structural in sheet form move up to 10 to 12 gauge. At the thin end, 24 to 26 gauge covers flashing and light duct work, and corrugated roofing panels are commonly 26 or 29 gauge with a protective coating.

When a supplier quotes you a gauge for a job, sanity-check it against the use. A "heavy duty" shelf panel quoted in 22 gauge (0.0299 in) will feel flimsy next to the same panel in 16 gauge, which is twice as thick and twice the weight per square foot.

Ordering steel sheet by gauge

Gauge is a nominal thickness. Mill tolerances under ASTM A568 allow the delivered sheet to run slightly above or below the table value, so for a part whose fit depends on exact thickness, specify the decimal — 0.0598 in — alongside the gauge, and measure the delivered sheet with a micrometer rather than trusting the label.

Also check which chart a quote is using. Some older references print the US Standard Gauge for uncoated steel, whose values differ slightly from the Manufacturers' Standard Gauge used here. If a supplier's 16 gauge shows 0.0625 inches, they are quoting the stainless series or an older table — the difference is small but real, and it is exactly the kind of mismatch the four-way chart on this site exists to catch.

Nearest steel gauge for metric thicknesses

Computed from the chart above: for each common metric size, the published steel gauge whose thickness is closest, with its actual thickness.

Related charts

• Sheet metal gauge chart (all four metals)
• Stainless steel gauge chart
• Aluminum gauge chart
• Galvanized gauge chart
• Gauge to mm converter
• All charts

Thickness values follow Manufacturers' Standard Gauge (ASTM A568); cross-checked against published supplier charts, November 2026.