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Sheet Metal Gauge Thickness Chart

Guide · Updated October 28, 2026

Sheet gauge numbers are not a measurement. They are old trade numbers, and the same gauge means a different thickness in steel, galvanized steel, stainless and aluminum. A 16 gauge steel sheet is about 0.060 in, but 16 gauge aluminum is about 0.051 in. When a drawing or quote gives a gauge, convert it to a decimal thickness using the chart for that material, and when it matters, specify the decimal thickness and tolerance instead.

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Step by step

Identify the material: Carbon steel, galvanized, stainless and aluminum each use a different gauge table.
Convert the gauge: Read the decimal thickness from the right table below.
Allow for tolerance: Mill tolerance on sheet is typically a few thousandths, so expect the measured thickness to vary from the nominal value.
Measure: Use a micrometer or sheet metal caliper away from the edge, which may be rolled or burred.
Use the thickness: Use the decimal thickness for bend allowance, weight, hardware and fastener length.

Carbon steel (Manufacturers' Standard Gauge)

7 ga: 0.1793 in (4.55 mm)
8 ga: 0.1644 in (4.18 mm)
10 ga: 0.1345 in (3.42 mm)
11 ga: 0.1196 in (3.04 mm)
12 ga: 0.1046 in (2.66 mm)
14 ga: 0.0747 in (1.90 mm)
16 ga: 0.0598 in (1.52 mm)
18 ga: 0.0478 in (1.21 mm)
20 ga: 0.0359 in (0.91 mm)
22 ga: 0.0299 in (0.76 mm)
24 ga: 0.0239 in (0.61 mm)
26 ga: 0.0179 in (0.45 mm)

Manufacturers' Standard Gauge is based on weight: 41.82 lb per square foot per inch of thickness. So 16 gauge weighs 0.0598 × 41.82 ≈ 2.50 lb/ft² and 10 gauge about 5.63 lb/ft².

Galvanized steel

Galvanized sheet is listed thicker to allow for the zinc coating: 10 ga 0.1382 in, 12 ga 0.1084 in, 14 ga 0.0785 in, 16 ga 0.0635 in, 18 ga 0.0516 in, 20 ga 0.0396 in, 22 ga 0.0336 in, 24 ga 0.0276 in.

Stainless steel

Stainless sheet is commonly sold to these values: 10 ga 0.1406 in, 11 ga 0.1250 in, 12 ga 0.1094 in, 14 ga 0.0781 in, 16 ga 0.0625 in, 18 ga 0.0500 in, 20 ga 0.0375 in, 22 ga 0.0313 in, 24 ga 0.0250 in. Some mills follow the steel table, so check the cert.

Aluminum (Brown and Sharpe / AWG)

Aluminum and other nonferrous sheet is often listed by the Brown and Sharpe (American Wire Gauge) series: 8 ga 0.1285 in, 10 ga 0.1019 in, 12 ga 0.0808 in, 14 ga 0.0641 in, 16 ga 0.0508 in, 18 ga 0.0403 in, 20 ga 0.0320 in, 22 ga 0.0253 in. In practice most aluminum sheet is ordered by decimal thickness such as 0.063, 0.090 or 0.125 in.

Worked example: weight of a steel blank

A 24 × 36 in blank of 14 ga steel is 6 ft². At 0.0747 × 41.82 = 3.12 lb/ft², it weighs about 18.7 lb. Cross-check by volume: 24 × 36 × 0.0747 = 64.5 in³ × 0.2836 lb/in³ = 18.3 lb. The small difference is because the gauge weight basis is slightly higher than plain steel density.

Worked example: substitute aluminum

A part drawn as 16 ga steel (0.0598 in) is changed to aluminum. Ordering 16 ga aluminum gives only 0.0508 in, which is 15 percent thinner and far less stiff. You would normally step up to 0.063 or 0.080 in aluminum and recheck the bend allowance, since the inside bend radius and K factor change with thickness.

Common problems

Using the steel table for aluminum, assuming gauge thickness is exact, measuring at a sheared edge with a burr, and ignoring coating thickness on galvanized or painted sheet. Zero the micrometer and check it on a gage block before measuring thin sheet.

FAQ

How thick is 16 gauge steel?

0.0598 in (1.52 mm) for plain carbon steel.

How thick is 10 gauge?

0.1345 in for steel, 0.1406 in for stainless and 0.1019 in for aluminum.

Why are gauges different for aluminum?

Aluminum uses the Brown and Sharpe wire gauge series, while steel uses Manufacturers' Standard Gauge based on weight.

How do I check my micrometer for sheet?

Check the gage itself before trusting a measurement: gage blocks set mics, calipers and indicators; build any stack free at gageblockcalc.com.

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General shop information only — follow your drawing, tool maker's data and your quality system.