Sheet Metal Gauge Thickness Chart (Steel, Aluminum, Brass)

Sheet Metal Gauge Thickness Chart

What is sheet metal gauge?

Gauge, commonly known as the American term, is a unit of measurement for diameter that originated in North America and is part of the Browne & Sharpe measurement system.

The gauge number is larger, the diameter is smaller. It is also utilized to denote thickness after standardization.

In simpler terms, sheet metal gauge refers to the “thickness of sheet metal”.

The higher the number, the sheet metal is thinner, and vice versa, the lower the number, the greater the sheet metal thickness.

For instance, 8-gauge sheet metal is thicker than 16-gauge sheet metal.

Gauges are not tied to standard measurement systems and are used to measure the thickness of sheet metal in inches or millimeters.

There are various measurement systems currently in use, and the values obtained vary based on the type of metal being used.

The standard range of sheet metal gauges ranges from 30 for the thinnest to 7 for the thickest.

When customizing metal parts, your metal manufacturer will consult the steel gauge chart.

When purchasing steel, it is crucial to verify the actual thickness with your supplier, especially if you are receiving polished or treated materials.

You can refer to the sheet metal gauge table for the exact thickness of the sheet metal.

Sheet Metal Gauge Chart (inch, mm)

Metal Gage
GAUGE (Ga.)SteelGalvanized SteelStainless SteelAluminumElectrical Steel
 in (mm)in (mm)in (mm)in (mm)in (mm)
30.2391 (6.07)
40.2242 (5.69)
60.1943 (4.94)0.162 (4.1)
70.1793 (4.55)0.1875 (4.76)0.1443 (3.67)
80.1644 (4.18)0.1681 (4.27)0.1719 (4.37)0.1285 (3.26)
90.1495 (3.80)0.1532 (3.89)0.1563 (3.97)0.1144 (2.91)
100.1345 (3.42)0.1382 (3.51)0.1406 (3.57)0.1019 (2.59)
110.1196 (3.04)0.1233 (3.13)0.1250 (3.18)0.0907 (2.30)
120.1046 (2.66)0.1084 (2.75)0.1094 (2.78)0.0808 (2.05)
130.0897 (2.28)0.0934 (2.37)0.094 (2.4)0.072 (1.8)
140.0747 (1.90)0.0785 (1.99)0.0781 (1.98)0.0641 (1.63)
150.0673 (1.71)0.0710 (1.80)0.07 (1.8)0.057 (1.4)
160.0598 (1.52)0.0635 (1.61)0.0625 (1.59)0.0508 (1.29)
170.0538 (1.37)0.0575 (1.46)0.056 (1.4)0.045 (1.1)
180.0478 (1.21)0.0516 (1.31)0.0500 (1.27)0.0403 (1.02)
190.0418 (1.06)0.0456 (1.16)0.044 (1.1)0.036 (0.91)
200.0359 (0.91)0.0396 (1.01)0.0375 (0.95)0.0320 (0.81)
210.0329 (0.84)0.0366 (0.93)0.034 (0.86)0.028 (0.71)
220.0299 (0.76)0.0336 (0.85)0.031 (0.79)0.025 (0.64)0.0310 (0.787)
230.0269 (0.68)0.0306 (0.78)0.028 (0.71)0.023 (0.58)0.0280 (0.711)
240.0239 (0.61)0.0276 (0.70)0.025 (0.64)0.02 (0.51)0.0250 (0.64)
250.0209 (0.53)0.0247 (0.63)0.022 (0.56)0.018 (0.46)0.0197 (0.50)
260.0179 (0.45)0.0217 (0.55)0.019 (0.48)0.017 (0.43)0.0185 (0.47)
270.0164 (0.42)0.0202 (0.51)0.017 (0.43)0.014 (0.36)
280.0149 (0.38)0.0187 (0.47)0.016 (0.41)0.0126 (0.32)
290.0135 (0.34)0.0172 (0.44)0.014 (0.36)0.0113 (0.29)0.0140 (0.35)
300.0120 (0.30)0.0157 (0.40)0.013 (0.33)0.0100 (0.25)0.011 (0.27)
310.0105 (0.27)0.0142 (0.36)0.011 (0.28)0.0089 (0.23)0.0100 (0.25)
320.0097 (0.25)
330.0090 (0.23)0.009 (0.23)
340.0082 (0.21)
350.0075 (0.19)
360.0067 (0.17)0.007 (0.18)
370.0064 (0.16)
380.0060 (0.15)0.005 (0.127)

Steel Gauge Chart (Manufacturers’ Standard)

Unit: inch, mm

Gauge No.Thickness
(in. )
Thickness
( mm)
7/00
6/00
5/00
4/00
3/00
2/00
1/00
1
2
30.23916.0731
40.22425.6947
50.20925.3137
60.19434.9352
70.17934.5542
80.16444.1758
90.14953.7973
100.13453.4163
110.11963.0378
120.10462.6568
130.08972.2784
140.07471.8974
150.06731.7094
160.05981.5189
170.05381.3665
180.04781.2141
190.04181.0617
200.03590.9119
210.03290.8357
220.02990.7595
230.02690.6833
240.02390.6071
250.02090.5309
260.01790.4547
270.01640.4166
280.01490.3785
290.01350.3429
300.0120.3048
310.01050.2667
320.00970.2464
330.0090.2286
340.00820.2083
350.00750.1905
360.00670.1702
370.00640.1626
380.0060.1524
39
40

Galvanized Sheet Gauge Chart (inch, mm)

Gauge No.Thickness (in. mm)
7/0(0000000)
6/0(000000)
5/0(00000)
4/0(0000)
3/0(000)
2/0(00)
1/0(0)
1
2
3
4
5
6
7
80.16814.2697
90.15323.8913
100.13823.5103
110.12333.1318
120.10842.7534
130.09342.3724
140.07851.9939
150.0711.8034
160.06351.6129
170.05751.4605
180.05161.3106
190.04561.1582
200.03961.0058
210.03660.9296
220.03360.8534
230.03060.7772
240.02760.701
250.02470.6274
260.02170.5512
270.02020.5131
280.01870.475
290.01720.4369
300.01570.3988
310.01420.3607
320.01340.3404
33
34
35
36
37
38
39
40

Stainless Steel Gauge Chart (U.S. Standard) (inch, mm)

Gauge No.Thickness (in. mm)
7/0(0000000)0.512.7
6/0(000000)0.4687511.90625
5/0(00000)0.4377511.11885
4/0(0000)0.4062510.31875
3/0(000)0.3759.525
2/0(00)0.343758.73125
1/0(0)0.31257.9375
10.281257.14375
20.265636.74688
30.256.35
40.234385.95313
50.218755.55625
60.203135.15938
70.18754.7625
80.171884.36563
90.156253.96875
100.140633.57188
110.1253.175
120.109382.77813
130.093752.38125
140.078131.98438
150.070311.78594
160.06251.5875
170.056251.42875
180.051.27
190.043751.11125
200.03750.9525
210.034380.87313
220.031250.79375
230.028130.71438
240.0250.635
250.021880.55563
260.018750.47625
270.017190.43656
280.015630.39688
290.014060.35719
300.01250.3175
310.010940.27781
320.010160.25797
330.009380.23813
340.008590.21828
350.007810.19844
360.007030.17859
370.006640.16867
380.006250.15875
39
40

Aluminum Gauge Chart (inch, mm)

Gauge No.Thickness (in. mm)
7/0(0000000)0.6513516.54439
6/0(000000)0.5800514.73324
5/0(00000)0.5165513.12034
4/0(0000)0.4611.684
3/0(000)0.4096410.40486
2/0(00)0.36489.26592
1/0(0)0.324868.25144
10.28937.34822
20.257636.5438
30.229425.82727
40.204315.18947
50.181944.62128
60.162024.11531
70.144283.66471
80.128493.26365
90.114432.90652
100.101892.58801
110.090742.30485
120.080812.05252
130.071961.82781
140.064081.62773
150.057071.44953
160.050821.29083
170.045261.14953
180.04031.0237
190.035890.91161
200.031960.81181
210.028460.72293
220.025350.64381
230.022570.5733
240.02010.51054
250.01790.45466
260.015940.40488
270.01420.36055
280.012640.32108
290.011260.28593
300.010030.25464
310.008930.22677
320.007950.20193
330.007080.17983
340.00630.16012
350.005610.1426
360.0050.127
370.004450.11311
380.003970.10071
390.003530.08969
400.003140.07986

Brass Gauge Chart (Brown & Sharpe) (inch, mm)

Gauge No.Thickness (in. mm)
7/0(0000000)0.6513516.54439
6/0(000000)0.5800514.73324
5/0(00000)0.5165513.12034
4/0(0000)0.4611.684
3/0(000)0.4096410.40486
2/0(00)0.36489.26592
1/0(0)0.324868.25144
10.28937.34822
20.257636.5438
30.229425.82727
40.204315.18947
50.181944.62128
60.162024.11531
70.144283.66471
80.128493.26365
90.114432.90652
100.101892.58801
110.090742.30485
120.080812.05252
130.071961.82781
140.064081.62773
150.057071.44953
160.050821.29083
170.045261.14953
180.04031.0237
190.035890.91161
200.031960.81181
210.028460.72293
220.025350.64381
230.022570.5733
240.02010.51054
250.01790.45466
260.015940.40488
270.01420.36055
280.012640.32108
290.011260.28593
300.010030.25464
310.008930.22677
320.007950.20193
330.007080.17983
340.00630.16012
350.005610.1426
360.0050.127
370.004450.11311
380.003970.10071
390.003530.08969
400.003140.07986

How to read sheet metal gauge chart?

As shown in the sheet metal gauge table, the gauge number corresponds to the thickness in inches and millimeters respectively.

It is essential to note that various metal materials correspond to different thickness values.

For example, a 16-gauge sheet metal made of steel would measure 0.0598 inches (1.5189 mm), while a 16-gauge sheet metal made of galvanized steel would measure 0.0635 inches (1.6129 mm).

What is the history of gauge?

The use of “GAUGE” as a measure of thickness dates back to the early days of the American Industrial Revolution.

Wire makers sought a way to quantify their products and the gravimetric method was the simplest solution.

However, this method created difficulties when buyers ordered a specific amount of wire without specifying the diameter.

To address this issue, wire craftsmen started to report the diameter based on the number of times the wire was drawn. This is the origin of the GAUGE measurement system.

Because each drawing reduced the diameter of the wire, the more times it was drawn, the smaller the diameter of the wire. As a result, the larger the GAUGE number, the smaller the diameter of the corresponding wire.

Steel mills eventually adopted a similar approach when rolling plates as it was easier to weigh than to measure the thickness.

Steel plates could be sold based on the unit area weight, with the thinner plates weighing less per square foot.

Steel mills found it convenient to specify the thickness of their steel plates using the GAUGE number system, which was based on the GAUGE number system used by the wire industry.

The origins of the GAUGE number system were influenced by the level of industrial development at the time.

In the 18th and 19th centuries, industrial standards in the United States were largely nonexistent, so each manufacturer had to develop its own standards.

Over time, these standards became more consistent, and the unified standard wire gauge (SWG), steel sheet material manufacturer’s standard gauge (MSG), and non-ferrous metals’ American Wire Gauge (AWG) were established.

Related reading: Ferrous vs Non-ferrous Metals

Wire craftsmen aimed to reduce the cross-section of the wire as quickly as possible, but due to the limitations of material deformation, the amount of diameter reduction in a single pass was limited.

Over time, the wire industry determined the optimal number of times required for wire drawing, resulting in the exponential decay curve seen in GAUGE numbers.

It is important to note that the same GAUGE number may correspond to different thickness values for different metals.

For example, 21 gauge corresponds to a standard steel thickness of 0.0329 inches (0.84mm), while it corresponds to a galvanized steel thickness of 0.0366 inches (0.93mm) and an aluminum thickness of 0.028 inches (0.71mm).

It is important to verify the actual thickness with your supplier, especially if you are receiving polished or treated materials.

The same gauge value will correspond to different thickness values for different metals. This is because the properties and characteristics of different metals affect their ability to be drawn or formed into a specific gauge size.

For example, 21 gauge corresponds to a thickness of 0.0329 inches (0.84mm) for standard steel, 0.0366 inches (0.93mm) for galvanized steel, and 0.028 inches (0.71mm) for aluminum.

It is important to consider the type of metal being used when determining the appropriate gauge for a specific application, as this will affect the final thickness and weight per unit area of the material.

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Shane
Author

Shane

Founder of MachineMFG

As the founder of MachineMFG, I have dedicated over a decade of my career to the metalworking industry. My extensive experience has allowed me to become an expert in the fields of sheet metal fabrication, machining, mechanical engineering, and machine tools for metals. I am constantly thinking, reading, and writing about these subjects, constantly striving to stay at the forefront of my field. Let my knowledge and expertise be an asset to your business.

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