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Sheet Metal Gauge Thickness Chart

Gauge is a legacy numbering system, and the same gauge number means a different thickness for steel, galvanized steel, stainless steel and aluminum. This lookup shows the actual decimal thickness for each so that quotes, drawings and purchase orders are unambiguous.

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GaugeMaterial / standardThickness (in)Thickness (mm)
7
Carbon steel (Manufacturers Standard)
0.1793
4.554
8
Carbon steel (Manufacturers Standard)
0.1644
4.176
10
Carbon steel (Manufacturers Standard)
0.1345
3.416
11
Carbon steel (Manufacturers Standard)
0.1196
3.038
12
Carbon steel (Manufacturers Standard)
0.1046
2.657
14
Carbon steel (Manufacturers Standard)
0.0747
1.897
16
Carbon steel (Manufacturers Standard)
0.0598
1.519
18
Carbon steel (Manufacturers Standard)
0.0478
1.214
20
Carbon steel (Manufacturers Standard)
0.0359
0.912
22
Carbon steel (Manufacturers Standard)
0.0299
0.759
24
Carbon steel (Manufacturers Standard)
0.0239
0.607
26
Carbon steel (Manufacturers Standard)
0.0179
0.455
28
Carbon steel (Manufacturers Standard)
0.0149
0.378
30
Carbon steel (Manufacturers Standard)
0.0120
0.305
8
Galvanized steel
0.1681
4.270
10
Galvanized steel
0.1382
3.510
12
Galvanized steel
0.1084
2.753
14
Galvanized steel
0.0785
1.994
16
Galvanized steel
0.0635
1.613
18
Galvanized steel
0.0516
1.311
20
Galvanized steel
0.0396
1.006
22
Galvanized steel
0.0336
0.853
24
Galvanized steel
0.0276
0.701
26
Galvanized steel
0.0217
0.551
28
Galvanized steel
0.0187
0.475
10
Stainless steel (common)
0.1406
3.571
11
Stainless steel (common)
0.1250
3.175
12
Stainless steel (common)
0.1094
2.779
14
Stainless steel (common)
0.0781
1.984
16
Stainless steel (common)
0.0625
1.588
18
Stainless steel (common)
0.0500
1.270
20
Stainless steel (common)
0.0375
0.953
22
Stainless steel (common)
0.0313
0.795
24
Stainless steel (common)
0.0250
0.635
10
Aluminum (Brown and Sharpe / AWG)
0.1019
2.588
12
Aluminum (Brown and Sharpe / AWG)
0.0808
2.052
14
Aluminum (Brown and Sharpe / AWG)
0.0641
1.628
16
Aluminum (Brown and Sharpe / AWG)
0.0508
1.290
18
Aluminum (Brown and Sharpe / AWG)
0.0403
1.024
20
Aluminum (Brown and Sharpe / AWG)
0.0320
0.813
22
Aluminum (Brown and Sharpe / AWG)
0.0253
0.643
24
Aluminum (Brown and Sharpe / AWG)
0.0201
0.511

Gauge numbers are not universal: the same number gives a different thickness for each material. Always put the thickness in inches or mm on the purchase order and in the item master. Stainless values are the commonly quoted nominal figures.

Clean up thickness attributes in your item master

Optional: a short review of how material thickness and spec could be structured in your ERP.

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How to use the chart

Type a gauge number or a material name into the search box to filter the table, then read the thickness in inches or millimeters. Export the filtered view to Excel or CSV if you need to share it with buyers or add it to an item master. Use the decimal thickness when you enter material in a nesting program, a CAD flat pattern or a bend table, because those tools work with real dimensions, not gauge numbers.

  • Search by gauge, such as 16, or by material, such as galvanized.
  • Copy the mm column into metric drawings and CAD material tables.
  • Confirm the standard with your supplier when thickness is critical.

Why gauge numbers differ by material

Gauge systems developed around the wire and sheet industries, not a single standard. Carbon steel sheet follows the Manufacturers Standard Gauge, galvanized steel includes the zinc coating, aluminum follows the Brown and Sharpe or AWG series, and stainless is commonly quoted using round fractional values. Higher gauge numbers mean thinner material. As a result, 16 gauge is about 1.52 mm in carbon steel, about 1.61 mm in galvanized steel and about 1.29 mm in aluminum.

  • Higher gauge number means thinner sheet.
  • Galvanized gauge is thicker than bare steel of the same number.
  • Plate is specified by thickness, not by gauge.

Tolerances and ordering

Gauge values are nominal. Mill tolerance on thickness varies by product, width and standard, and coatings add thickness. For parts where bend allowance, press brake tonnage or fit-up matters, measure the actual sheet with a micrometer. Put the nominal thickness in millimeters or inches, the material specification and the tolerance class on the purchase order. In your ERP item master, store thickness as a numeric attribute so it can drive nesting, costing and weight calculations.

  • Order by decimal thickness plus material specification.
  • Measure actual stock before setting a K-factor.

Common mistakes

The usual mistake is assuming that one gauge table covers every metal. Another is confusing galvanized and bare steel thickness, or ordering aluminum with a steel gauge number. Drawings that say only 14 gauge force the buyer and the programmer to guess. Convert gauge to decimal thickness once, record it in the item master, and use that value everywhere downstream.

  • Never reuse a steel gauge number for aluminum.
  • Never leave gauge as the only thickness on a drawing.

Frequently Asked Questions

What is 16 gauge steel in mm?

Carbon steel 16 gauge on the Manufacturers Standard Gauge is 0.0598 inch, about 1.52 mm. Galvanized 16 gauge is slightly thicker at 0.0635 inch, about 1.61 mm, because the coating is included.

Is a higher gauge number thicker or thinner?

Thinner. 10 gauge steel is about 3.4 mm, while 20 gauge steel is about 0.9 mm. The only exception to think about is plate and heavy sheet, which is usually ordered by thickness rather than gauge.

Why is aluminum gauge different from steel?

Because aluminum sheet uses the Brown and Sharpe (AWG) series, which is a different numbering system from the steel standard. Always quote aluminum by decimal thickness to avoid mix-ups.

Should I use gauge on drawings?

It is better not to. Specify thickness in mm or inches with the material specification. Gauge alone is ambiguous across materials and standards and can lead to wrong purchases.

If your item master still holds gauge numbers as free text, Netray can help clean up thickness attributes and link them to costing and nesting data in your ERP.

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