Understanding Sheet Metal Gauge Thickness


Why is sheet metal thickness described as a gauge size?

Gauge system are used to described size. Wire sizes, ear piercing's and sheet metal all use the term gauge to describe size. The sheet metal gauge system stems from the wire gauge system. The gauge size of a raw piece of wire was 0. Thinner wire was produced by drawing the wire through a drawing die and with each draw its gauge size increased by 1. The same principals were applied to sheet metal each time it was rolled.

How to convert from gauge to thickness?

The only way to convert from gauge size to thickness is with a gauge thickness chart for the material. Since gauge size wasn't based on a particular thickness but instead the number of times it passed through the machine, each manufacturer had their own specifications for what thickness material at a gauge was. Later the Manufacturer's Standard Gauge (MSG) defined gauge sizes by arbitrarily designating pound per square foot values for each material. This provided clarity because material was being sold and purchased by weight. The thickness could be determined from the density which later the MSG also defined based upon material average density.

The gauge system wasn't designed for the customers of today that need specific material thicknesses, it was designed for the manufacturers of the passed that sold based upon weight. This creates some challenges for today's designers that need to remember to convert the dimensions on their designs when switching material thicknesses. International standards outside the US have evolved away from gauge size and discourage its use.

Sheet Metal Gauge Thickness Charts

Gauge Thickness Cart - CARBON STEEL
Gauge Size Thickness [inch] Thickness [mm] Lb/ft2
26 0.0179 0.45 0.750
25 0.0209 0.53 0.875
24 0.0239 0.61 1.000
23 0.0269 0.68 1.125
22 0.0299 0.76 1.250
21 0.0329 0.84 1.375
20 0.0359 0.91 1.500
19 0.0418 1.06 1.750
18 0.0478 1.21 2.000
17 0.0538 1.37 2.250
16 0.0598 1.52 2.500
15 0.0673 1.71 2.813
14 0.0747 1.90 3.125
13 0.0897 2.28 3.750
12 0.1046 2.66 4.375
11 0.1196 3.04 5.000
10 0.1345 3.42 5.625
9 0.1495 3.80 6.250
8 0.1644 4.18 6.875
7 0.1793 4.55 7.500
Gauge Thickness Cart - GALVANIZED STEEL
Gauge Size Thickness [inch] Thickness [mm] Lb/ft2
26 0.022 0.56 0.906
25 0.025 0.64 1.031
24 0.028 0.71 1.156
23 0.031 0.79 1.281
22 0.034 0.86 1.406
21 0.037 0.94 1.531
20 0.040 1.02 1.656
19 0.046 1.17 1.906
18 0.052 1.32 2.156
17 0.058 1.47 2.406
16 0.064 1.63 2.656
15 0.071 1.80 2.969
14 0.079 2.01 3.281
13 0.093 2.36 3.906
12 0.108 2.74 4.531
11 0.123 3.12 5.156
10 0.138 3.51 5.781
9 0.153 3.89 6.406
8 0.168 4.27 7.031
Gauge Thickness Cart - STAINLESS STEEL
Gauge Size Thickness [inch] Thickness [mm] Lb/ft2
26 0.0187 0.47 0.756
25 0.0219 0.56
24 0.0250 0.64 1.008
23 0.0281 0.71
22 0.0312 0.79 1.26
21 0.0344 0.87
20 0.0375 0.95 1.512
19 0.0437 1.11
18 0.0500 1.27 2.016
17 0.0562 1.43
16 0.0625 1.59 2.52
15 0.0703 1.79
14 0.0781 1.98 3.15
13 0.0937 2.38
12 0.1094 2.78 4.41
11 0.1250 3.18 5.04
10 0.1406 3.57 5.67
9 0.1562 3.97
8 0.1719 4.37 6.93
7 0.1875 4.76 7.871
Gauge Thickness Cart - ALUMINUM
Gauge Size Thickness [inch] Thickness [mm] Lb/ft2
26 0.0159 0.40 0.224
25 0.0179 0.45 0.253
24 0.0201 0.51 0.284
23 0.0226 0.57 0.319
22 0.0253 0.64 0.357
21 0.0285 0.72 0.402
20 0.0320 0.81 0.452
19 0.0359 0.91 0.507
18 0.0403 1.02 0.569
17 0.0453 1.15 0.639
16 0.0508 1.29 0.717
15 0.0571 1.45 0.806
14 0.0641 1.63 0.905
13 0.0720 1.83 1.016
12 0.0808 2.05 1.140
11 0.0907 2.30 1.280
10 0.1019 2.59 1.438
9 0.1144 2.91 1.614
8 0.1285 3.26 1.813
7 0.1443 3.67 2.036
Gauge Carbon Steel Galvanized Steel Stainless Steel Aluminum
Thickness [in] Lb/ft2 Thickness [in] Lb/ft2 Thickness [in] Lb/ft2 Thickness [in] Lb/ft2
26 0.0179 0.750 0.022 0.906 0.0187 0.756 0.0159 0.224
25 0.0209 0.875 0.025 1.031 0.0219 0.0179 0.253
24 0.0239 1.000 0.028 1.156 0.0250 1.008 0.0201 0.284
23 0.0269 1.125 0.031 1.281 0.0281 0.0226 0.319
22 0.0299 1.250 0.034 1.406 0.0312 1.26 0.0253 0.357
21 0.0329 1.375 0.037 1.531 0.0344 0.0285 0.402
20 0.0359 1.500 0.040 1.656 0.0375 1.512 0.0320 0.452
19 0.0418 1.750 0.046 1.906 0.0437 0.0359 0.507
18 0.0478 2.000 0.052 2.156 0.0500 2.016 0.0403 0.569
17 0.0538 2.250 0.058 2.406 0.0562 0.0453 0.639
16 0.0598 2.500 0.064 2.656 0.0625 2.52 0.0508 0.717
15 0.0673 2.813 0.071 2.969 0.0703 0.0571 0.806
14 0.0747 3.125 0.079 3.281 0.0781 3.15 0.0641 0.905
13 0.0897 3.750 0.093 3.906 0.0937 0.0720 1.016
12 0.1046 4.375 0.108 4.531 0.1094 4.41 0.0808 1.140
11 0.1196 5.000 0.123 5.156 0.1250 5.04 0.0907 1.280
10 0.1345 5.625 0.138 5.781 0.1406 5.67 0.1019 1.438
9 0.1495 6.250 0.153 6.406 0.1562 0.1144 1.614
8 0.1644 6.875 0.168 7.031 0.1719 6.93 0.1285 1.813
7 0.1793 7.500 0.1875 7.871 0.1443 2.036
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