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Reference Chart

Sheet Metal Thickness Gauge Chart

Convert gauge numbers to inches and millimeters for steel, aluminum, and stainless steel. This chart covers gauges 7 through 30.

Showing 24 of 24 gauges
Gauge ▲ Steel (in) ▲ Steel (mm) ▲ Aluminum (in) ▲ Aluminum (mm) ▲ Stainless (in) ▲ Stainless (mm) ▲
7 0.1793 4.554 0.1443 3.665 0.1875 4.763
8 0.1644 4.176 0.1285 3.264 0.1719 4.366
9 0.1495 3.797 0.1144 2.906 0.1563 3.969
10 0.1345 3.416 0.1019 2.588 0.1406 3.571
11 0.1196 3.038 0.0907 2.304 0.1250 3.175
12 0.1046 2.657 0.0808 2.052 0.1094 2.779
13 0.0897 2.278 0.0720 1.829 0.0938 2.382
14 0.0747 1.897 0.0641 1.628 0.0781 1.984
15 0.0673 1.709 0.0571 1.450 0.0703 1.786
16 0.0598 1.519 0.0508 1.290 0.0625 1.588
17 0.0538 1.367 0.0453 1.151 0.0563 1.429
18 0.0478 1.214 0.0403 1.024 0.0500 1.270
19 0.0418 1.062 0.0359 0.912 0.0438 1.113
20 0.0359 0.912 0.0320 0.813 0.0375 0.953
21 0.0329 0.836 0.0285 0.724 0.0344 0.874
22 0.0299 0.759 0.0253 0.643 0.0313 0.795
23 0.0269 0.683 0.0226 0.574 0.0281 0.714
24 0.0239 0.607 0.0201 0.511 0.0250 0.635
25 0.0209 0.531 0.0179 0.455 0.0219 0.556
26 0.0179 0.455 0.0159 0.404 0.0188 0.478
27 0.0164 0.417 0.0142 0.361 0.0172 0.437
28 0.0149 0.378 0.0126 0.320 0.0156 0.396
29 0.0135 0.343 0.0113 0.287 0.0141 0.358
30 0.0120 0.305 0.0100 0.254 0.0125 0.318
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Notes on This Chart

  • Steel values follow the Manufacturers' Standard Gauge (MSG) for sheet steel.
  • Aluminum values follow the Brown & Sharpe (B&S/AWG) gauge standard.
  • Stainless steel values follow the stainless steel sheet gauge standard.
  • Actual thickness may vary slightly by supplier and mill tolerance.
  • Always confirm the exact thickness with your metal supplier before ordering.

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Frequently Asked Questions

What does sheet metal gauge mean?

Gauge is a number that tells you how thick a piece of sheet metal is. A lower number means thicker metal. A higher number means thinner metal. For example, 10 gauge steel is about 0.135 inches thick. 22 gauge steel is about 0.030 inches thick.

Why do gauge numbers differ between steel, aluminum, and stainless?

Each metal type uses a different gauge standard. Steel uses the Manufacturers' Standard Gauge. Aluminum uses the Brown and Sharpe gauge. Stainless steel has its own standard. That is why the same gauge number gives a different thickness for each metal. Always check a chart for the right metal.

What gauge is best for CNC sheet metal parts?

Most CNC sheet metal parts use 10 to 20 gauge. Thinner sheets (22 to 30 gauge) work well for covers, brackets, and light enclosures. Thicker sheets (7 to 12 gauge) handle heavy loads and structural parts. Pick the gauge based on how strong the part needs to be.

How do I convert gauge to inches or mm?

Use a gauge chart like this one. Find the gauge number on the left. Then read across to your metal type. The chart shows thickness in both inches and millimeters. Always double-check the exact value with your metal supplier before you start cutting.

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