SHEET METAL GAUGE CHART

SHEET METAL GAUGES

Sheet metal thickness is denoted by gauge, sometimes spelled gage, which indicates a standard thickness before processing.

Processing may include polishing, or the applying of protective plastics which will decrease or increase a sheet's thickness respectively.

As the gauge number increases the material's thickness decreases.

Gauge # Standard Steel
(Inches)
Standard Steel
(mm)
Strip / Tubing
(Inches)
Non-Ferrous /
Aluminum
(Inches)
Non-Ferrous /
Aluminum
(mm)
Galvanized
Steel
(Inches)
Galvanized
Steel
(mm)
US Standard
0000000 - - - - - - - 0.5000
000000 - - - 0.5800 14.732 - - 0.4688
00000 - - 0.500 0.5165 13.119 - - 0.4375
0000 - - 0.454 0.4600 11.684 - - 0.4063
000 - - 0.425 0.4096 10.404 - - 0.3750
00 - - 0.380 0.3648 9.266 - - 0.3438
0 - - 0.340 0.3249 8.252 - - 0.3125
1 - - 0.300 0.2893 7.348 - - 0.2813
2 - - 0.284 0.2576 6.543 - - 0.2656
3 0.2391 6.073 0.259 0.2294 5.827 - - 0.2500
4 0.2242 5.695 0.238 0.2043 5.189 - - 0.2344
5 0.2092 5.314 0.220 0.1819 4.620 - - 0.2188
6 0.1943 4.935 0.203 0.1620 4.115 - - 0.2031
7 0.1793 4.554 0.180 0.1443 3.665 - - 0.1875
8 0.1644 4.176 0.165 0.1285 3.264 - 4.270 0.1719
9 0.1495 3.797 0.148 0.1144 2.906 0.1532 3.891 0.1563
10 0.1345 3.416 0.134 0.1019 2.588 0.1382 3.510 0.1406
11 0.1196 3.038 0.120 0.0907 2.304 0.1233 3.132 0.1250
12 0.1046 2.657 0.109 0.0808 2.052 0.1084 2.753 0.1094
13 0.0897 2.278 0.095 0.0720 1.829 0.0934 2.372 0.0938
14 0.0747 1.897 0.083 0.0641 1.628 0.0785 1.994 0.0781
15 0.0673 1.709 0.072 0.0571 1.450 0.0710 1.803 0.0703
16 0.0598 1.519 0.065 0.0508 1.290 0.0635 1.613 0.0625
17 0.0538 1.367 0.058 0.0453 1.151 0.0575 1.461 0.0563
18 0.0478 1.214 0.049 0.0403 1.024 0.0516 1.311 0.0500
19 0.0418 1.062 0.042 0.0359 0.912 0.0456 1.158 0.0438
20 0.0359 0.912 0.035 0.0320 0.813 0.0396 1.006 0.0375
21 0.0329 0.836 0.032 0.0285 0.724 0.0366 0.930 0.0344
22 0.0299 0.759 0.028 0.0253 0.643 0.0306 0.853 0.0313
23 0.0269 0.683 0.025 0.0226 0.574 0.0276 0.777 0.0281
24 0.0239 0.607 0.022 0.0201 0.511 0.0247 0.701 0.0250
25 0.0209 0.531 0.020 0.0179 0.455 0.0217 0.627 0.0219
26 0.0179 0.455 0.018 0.0159 0.404 0.0202 0.551 0.0188
27 0.0164 0.417 - 0.0142 0.361 0.0187 0.513 0.0172
28 0.0149 0.378 - 0.0126 0.320 0.0172 0.475 0.0156
29 0.0135 0.343 - 0.0113 0.287 0.0157 0.437 0.0141
30 0.0120 0.305 - 0.0100 0.254 0.0142 0.399 0.0125
31 0.0105 0.267 - 0.0089 0.226 0.0134 0.361 0.0109
32 0.0097 0.246 - 0.0080 0.203 - 0.340 0.0102
33 0.0090 0.229 - 0.0071 0.180 - - 0.0094
34 0.0082 0.208 - 0.0063 0.160 - - 0.0086
35 0.0075 0.191 - 0.0056 0.140 - - 0.0078
36 0.0067 0.170 - 0.0050 0.127 - - 0.0070
37 - 0.163 - 0.0045 0.114 - - 0.0066
38 - 0.152 - 0.004 0.102 - - 0.0063
39 - - - - 0.089 - - 0.0059
40 - - - - 0.079 - - 0.0055
41 - - - - - - - 0.0053
42 - - - - - - - 0.0051
43 - - - - - - - 0.0049
44 - - - - - - - 0.0040

SHEET METAL THICKNESS TOLERANCES

Because sheets aremanufactured by rolling to the desired thickness there can be some crowning of the rollers, resulting in a thinner sheet on the edges compared to the center, this is shown in the table below.

STEEL / STAINLESS STEEL   ALUMINIUM
THICKNESS 36'' WIDE SHEET 48'' WIDE SHEET   THICKNESS 36'' WIDE SHEET 48'' WIDE SHEET
0.170 -0.030 0.0015 0.002   0.018 - 0.028 0.002 0.0025
0.031 - 0.041 0.002 0.003   0.029 - 0.036 0.002 0.0025
0.042 - 0.059 0.003 0.004   0.037 - 0.045 0.0025 0.003
0.060 - 0.073 0.003 0.0045   0.046 - 0.068 0.003 0.004
0.074 - 0.084 0.004 0.0055   0.069 - 0.076 0.003 0.004
0.085 - 0.099 0.004 0.006   0.077 - 0.096 0.0035 0.004
0.100 - 0.115 0.005 0.007   0.097 - 0.108 0.004 0.005
0.116 - 0.131 0.005 0.0075   0.109 - 0.125 0.0045 0.005
0.132 - 0.146 0.006 0.009   0.126 - 0.140 0.0045 0.005
0.147 - 0.187 0.007 0.0105   0.141 - 0.172 0.006 0.008
  0.173 - 0.203 0.007 0.010
  0.204 - 0.249 0.009 0.011

GALVANISED COATING THICKNESSES

As you can see from our first chart the galvanized columns are thicker than the regular steel.

After galvanizing, the continuous zinc coating is physically wiped using air knives to produce a uniform coating across the width of the strip.
The uniform coating consists almost entirely of unalloyed zinc and has sufficient ductility to withstand deep drawing or bending without damage.
A variety of coating weights and types are available, ranging up to just over 3 mils (76 µm) per side.
One of the most common zinc coatings is Class G90, which has 0.9 oz/ft² of sheet (total both sides) or about 0.80 mils (20 µm) thickness per side.
Continuous sheet galvanized coatings often get confused with batch hot-dip galvanized coatings because the term galvanizing is used interchangeably.
The tables below compare the available coating grades of continuous and batch hot-dip galvanizing and their
corresponding coating thicknesses.

CONTINIOUS SHEET GALVANISING

The number following the "G" coating grade designation correlates to the total thickness of zinc applied to both sides of the steel sheet.

DESIGNATION BOTH SIDES ONE SIDE
COATING GRADE oz/ft² oz/ft² mm um
G360 3.60 1.80 3.24 82.3
G300 3.00 1.50 2.70 68.6
G235 2.35 1.18 2.12 53.7
G210 2.10 1.05 1.89 48.0
G185 1.85 0.93 1.67 42.3
G165 1.65 0.83 1.49 37.7
G140 1.40 0.70 1.26 32.0
G115 1.15 0.58 1.04 26.3
G90 0.90 0.45 0.81 20.6
G60 / A60 0.60 0.30 0.54 13.7
G40 / A40 0.40 0.20 0.36 9.1
G30 / A30 0.30 0.15 0.27 6.9
G01 NO MINIMUM - - -

HOT DIP GALVANISING

Hot-dip Galvanizing: Coating grades are determined by the steel thickness and type.
Coating grades correspond to minimum zinc coating thickness on one side.

It is important to remember these are minimum coating thicknesses the galvanizer must achieve;
however, thicker coatings are common, assuring conformance to.

ONE SIDE
COATING GRADE oz/ft² mm um
100 2.19 3.94 100
85 1.86 3.35 85
80 17.5 3.15 80
75 1.64 2.95 75
65 1.42 2.56 65
60 1.31 2.36 60
55 1.20 2.17 55
50 1.10 1.97 50
45 0.98 1.77 45
35 0.77 1.38 35