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

There is no conversion formula due to the difference between Ga. scale and inch.

However, you can convert gauge to inches or metric units based on the sheet metal gauge chart below.

Sheet Metal Gauge Sizes Chart In Inch and mm

The comparison of different unit systems is shown in the table below.

Metal Gage

Steel Gauge Chart (Manufacturers’ Standard) Unit: 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 0.2391 6.0731
4 0.2242 5.6947
5 0.2092 5.3137
6 0.1943 4.9352
7 0.1793 4.5542
8 0.1644 4.1758
9 0.1495 3.7973
10 0.1345 3.4163
11 0.1196 3.0378
12 0.1046 2.6568
13 0.0897 2.2784
14 0.0747 1.8974
15 0.0673 1.7094
16 0.0598 1.5189
17 0.0538 1.3665
18 0.0478 1.2141
19 0.0418 1.0617
20 0.0359 0.9119
21 0.0329 0.8357
22 0.0299 0.7595
23 0.0269 0.6833
24 0.0239 0.6071
25 0.0209 0.5309
26 0.0179 0.4547
27 0.0164 0.4166
28 0.0149 0.3785
29 0.0135 0.3429
30 0.012 0.3048
31 0.0105 0.2667
32 0.0097 0.2464
33 0.009 0.2286
34 0.0082 0.2083
35 0.0075 0.1905
36 0.0067 0.1702
37 0.0064 0.1626
38 0.006 0.1524
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
8 0.1681 4.2697
9 0.1532 3.8913
10 0.1382 3.5103
11 0.1233 3.1318
12 0.1084 2.7534
13 0.0934 2.3724
14 0.0785 1.9939
15 0.071 1.8034
16 0.0635 1.6129
17 0.0575 1.4605
18 0.0516 1.3106
19 0.0456 1.1582
20 0.0396 1.0058
21 0.0366 0.9296
22 0.0336 0.8534
23 0.0306 0.7772
24 0.0276 0.701
25 0.0247 0.6274
26 0.0217 0.5512
27 0.0202 0.5131
28 0.0187 0.475
29 0.0172 0.4369
30 0.0157 0.3988
31 0.0142 0.3607
32 0.0134 0.3404
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) 0.5 12.7
6/0 (000000) 0.46875 11.90625
5/0 (00000) 0.43775 11.11885
4/0 (0000) 0.40625 10.31875
3/0 (000) 0.375 9.525
2/0 (00) 0.34375 8.73125
1/0 (0) 0.3125 7.9375
1 0.28125 7.14375
2 0.26563 6.74688
3 0.25 6.35
4 0.23438 5.95313
5 0.21875 5.55625
6 0.20313 5.15938
7 0.1875 4.7625
8 0.17188 4.36563
9 0.15625 3.96875
10 0.14063 3.57188
11 0.125 3.175
12 0.10938 2.77813
13 0.09375 2.38125
14 0.07813 1.98438
15 0.07031 1.78594
16 0.0625 1.5875
17 0.05625 1.42875
18 0.05 1.27
19 0.04375 1.11125
20 0.0375 0.9525
21 0.03438 0.87313
22 0.03125 0.79375
23 0.02813 0.71438
24 0.025 0.635
25 0.02188 0.55563
26 0.01875 0.47625
27 0.01719 0.43656
28 0.01563 0.39688
29 0.01406 0.35719
30 0.0125 0.3175
31 0.01094 0.27781
32 0.01016 0.25797
33 0.00938 0.23813
34 0.00859 0.21828
35 0.00781 0.19844
36 0.00703 0.17859
37 0.00664 0.16867
38 0.00625 0.15875
39
40

Aluminum Gauge Chart (inch, mm)

Gauge No. Thickness (in. mm)
7/0 (0000000) 0.65135 16.54439
6/0 (000000) 0.58005 14.73324
5/0 (00000) 0.51655 13.12034
4/0 (0000) 0.46 11.684
3/0 (000) 0.40964 10.40486
2/0 (00) 0.3648 9.26592
1/0 (0) 0.32486 8.25144
1 0.2893 7.34822
2 0.25763 6.5438
3 0.22942 5.82727
4 0.20431 5.18947
5 0.18194 4.62128
6 0.16202 4.11531
7 0.14428 3.66471
8 0.12849 3.26365
9 0.11443 2.90652
10 0.10189 2.58801
11 0.09074 2.30485
12 0.08081 2.05252
13 0.07196 1.82781
14 0.06408 1.62773
15 0.05707 1.44953
16 0.05082 1.29083
17 0.04526 1.14953
18 0.0403 1.0237
19 0.03589 0.91161
20 0.03196 0.81181
21 0.02846 0.72293
22 0.02535 0.64381
23 0.02257 0.5733
24 0.0201 0.51054
25 0.0179 0.45466
26 0.01594 0.40488
27 0.0142 0.36055
28 0.01264 0.32108
29 0.01126 0.28593
30 0.01003 0.25464
31 0.00893 0.22677
32 0.00795 0.20193
33 0.00708 0.17983
34 0.0063 0.16012
35 0.00561 0.1426
36 0.005 0.127
37 0.00445 0.11311
38 0.00397 0.10071
39 0.00353 0.08969
40 0.00314 0.07986

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

Gauge No. Thickness (in. mm)
7/0 (0000000) 0.65135 16.54439
6/0 (000000) 0.58005 14.73324
5/0 (00000) 0.51655 13.12034
4/0 (0000) 0.46 11.684
3/0 (000) 0.40964 10.40486
2/0 (00) 0.3648 9.26592
1/0 (0) 0.32486 8.25144
1 0.2893 7.34822
2 0.25763 6.5438
3 0.22942 5.82727
4 0.20431 5.18947
5 0.18194 4.62128
6 0.16202 4.11531
7 0.14428 3.66471
8 0.12849 3.26365
9 0.11443 2.90652
10 0.10189 2.58801
11 0.09074 2.30485
12 0.08081 2.05252
13 0.07196 1.82781
14 0.06408 1.62773
15 0.05707 1.44953
16 0.05082 1.29083
17 0.04526 1.14953
18 0.0403 1.0237
19 0.03589 0.91161
20 0.03196 0.81181
21 0.02846 0.72293
22 0.02535 0.64381
23 0.02257 0.5733
24 0.0201 0.51054
25 0.0179 0.45466
26 0.01594 0.40488
27 0.0142 0.36055
28 0.01264 0.32108
29 0.01126 0.28593
30 0.01003 0.25464
31 0.00893 0.22677
32 0.00795 0.20193
33 0.00708 0.17983
34 0.0063 0.16012
35 0.00561 0.1426
36 0.005 0.127
37 0.00445 0.11311
38 0.00397 0.10071
39 0.00353 0.08969
40 0.00314 0.07986

Sheet Metal Gauge Chart (inch, mm)

GAUGE (Ga.) Steel Galvanized Steel Stainless Steel Aluminum Electrical Steel
  in (mm) in (mm) in (mm) in (mm) in (mm)
3 0.2391 (6.07)
4 0.2242 (5.69)
6 0.1943 (4.94) 0.162 (4.1)
7 0.1793 (4.55) 0.1875 (4.76) 0.1443 (3.67)
8 0.1644 (4.18) 0.1681 (4.27) 0.1719 (4.37) 0.1285 (3.26)
9 0.1495 (3.80) 0.1532 (3.89) 0.1563 (3.97) 0.1144 (2.91)
10 0.1345 (3.42) 0.1382 (3.51) 0.1406 (3.57) 0.1019 (2.59)
11 0.1196 (3.04) 0.1233 (3.13) 0.1250 (3.18) 0.0907 (2.30)
12 0.1046 (2.66) 0.1084 (2.75) 0.1094 (2.78) 0.0808 (2.05)
13 0.0897 (2.28) 0.0934 (2.37) 0.094 (2.4) 0.072 (1.8)
14 0.0747 (1.90) 0.0785 (1.99) 0.0781 (1.98) 0.0641 (1.63)
15 0.0673 (1.71) 0.0710 (1.80) 0.07 (1.8) 0.057 (1.4)
16 0.0598 (1.52) 0.0635 (1.61) 0.0625 (1.59) 0.0508 (1.29)
17 0.0538 (1.37) 0.0575 (1.46) 0.056 (1.4) 0.045 (1.1)
18 0.0478 (1.21) 0.0516 (1.31) 0.0500 (1.27) 0.0403 (1.02)
19 0.0418 (1.06) 0.0456 (1.16) 0.044 (1.1) 0.036 (0.91)
20 0.0359 (0.91) 0.0396 (1.01) 0.0375 (0.95) 0.0320 (0.81)
21 0.0329 (0.84) 0.0366 (0.93) 0.034 (0.86) 0.028 (0.71)
22 0.0299 (0.76) 0.0336 (0.85) 0.031 (0.79) 0.025 (0.64) 0.0310 (0.787)
23 0.0269 (0.68) 0.0306 (0.78) 0.028 (0.71) 0.023 (0.58) 0.0280 (0.711)
24 0.0239 (0.61) 0.0276 (0.70) 0.025 (0.64) 0.02 (0.51) 0.0250 (0.64)
25 0.0209 (0.53) 0.0247 (0.63) 0.022 (0.56) 0.018 (0.46) 0.0197 (0.50)
26 0.0179 (0.45) 0.0217 (0.55) 0.019 (0.48) 0.017 (0.43) 0.0185 (0.47)
27 0.0164 (0.42) 0.0202 (0.51) 0.017 (0.43) 0.014 (0.36)
28 0.0149 (0.38) 0.0187 (0.47) 0.016 (0.41) 0.0126 (0.32)
29 0.0135 (0.34) 0.0172 (0.44) 0.014 (0.36) 0.0113 (0.29) 0.0140 (0.35)
30 0.0120 (0.30) 0.0157 (0.40) 0.013 (0.33) 0.0100 (0.25) 0.011 (0.27)
31 0.0105 (0.27) 0.0142 (0.36) 0.011 (0.28) 0.0089 (0.23) 0.0100 (0.25)
32 0.0097 (0.25)
33 0.0090 (0.23) 0.009 (0.23)
34 0.0082 (0.21)
35 0.0075 (0.19)
36 0.0067 (0.17) 0.007 (0.18)
37 0.0064 (0.16)
38 0.0060 (0.15) 0.005 (0.127)

FAQs About Sheet Metal Gauge Thickness

What is sheet metal gauge?

GAUGE (abbreviated as Ga.), Which Americans call, is a unit of measurement of diameter that originated in North America and belongs to the Browne & Sharpe measurement system.

The larger the number of GAUGE is, the smaller the diameter is. It is also used to indicate thickness after promotion.

Simply put, sheet metal gauge refers to “sheet metal thickness”. The larger the number, the thinner the metal plate.

Conversely, the smaller the number, the greater the sheet metal thickness.

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

Gauges are independent of common measurement systems and are used to determine sheet metal thickness in inches or millimeters.

Various measuring systems are used today, and the measured values vary depending on the type of metal used.

Standard sheet metal gauges range from 30 at the thinner end to 7 at the thicker end.

Before customizing metal parts, your metal manufacturer will refer to the steel gauge sheet.

When purchasing steel, be sure to check your actual thickness with your supplier, especially when you receive polished or treated materials.

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

How to read sheet metal gauge chart?

As can be seen from the sheet metal gauge table, the gauge number corresponds to the thickness in inches and millimeters respectively.

However, it should be noted that different metal materials correspond to different thickness values.

For example, 16-gauge sheet made from steel would be 0.0598 inch and 1.5189 mm, while 16-gauge sheet metal made from galvanized sheet would be 0.0635 inch and 1.6129mm

The history of gauge

In fact, the use of “GAUGE” to indicate thickness can be traced back to the beginning of the American Industrial Revolution.

At the time, people who produced wire needed a way to quantify the products they sold.

Of course, the easiest method is the gravimetric method.

But if the buyer only proposes to buy 15 pounds of wire, but does not specify the diameter of the wire, it will also bring a lot of trouble.

Therefore, the wire craftsmen will report the diameter according to the number of wire drawing they have performed.

This is the origin of GAUGE.

Because each drawing will reduce the diameter of the wire, the more times it is drawn, the smaller the diameter of the wire.

Therefore, the larger the GAUGE number, the smaller the diameter of the corresponding wire.

At that time, steel mills found that it was easier to weigh than to measure thickness when rolling plates.

Therefore, similar to metal wires, steel plates can be sold using the unit area weight method.

The thinner the corresponding steel plate, the smaller the weight per square foot.

Therefore, steel mills believe that the most convenient way to specify the thickness of steel plates is to establish the steel plate’s GAUGE number system by referring to the GAUGE number system adopted by the wire industry.

As for the historical origin of the GAUGE number, it may be determined by the level of productivity development at that time.

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

Over time and with the improvement of the industry level, the standards of these manufacturers have gradually become consistent, and the unified standard wire gauge (SWG), steel sheet material manufacturer’s standard gauge (MSG) and non-ferrous metals’ American Wire Gauge (AWG) have gradually been established.

Related reading: Ferrous vs Non-ferrous Metals

Regarding GAUGE numbers, a confusing phenomenon is that when you change from one GAUGE number to the next GAUGE number, the change in thickness and weight per unit area is not constant.

In fact, if you graph these numbers, you will see an “exponential decay curve”.

In other words, the difference between consecutive GAUGE numbers becomes smaller as the GAUGE value increases.

For example, the difference between 10Ga. and 11Ga. is 0.0149″, while the difference between 35Ga. and 36Ga is only 0.0008″.

The reason for this difference can be traced back to the origin of the GAUGE number: wire making, which depends on the amount of reduction that can be achieved with each drawing.

In order to manufacture thin metal wires, wire craftsmen hope to reduce the cross-section as soon as possible.

However, due to the limitation of the metallurgical mechanism of material deformation, the amount of diameter reduction in a single pass is limited.

Over time, the wire industry has determined the optimal number of times required for wire drawing.

This is the root cause of the exponential decay curve we see.

It should be noted that when the non-ferrous metal plate and the steel plate are both at a certain Ga. number, the thickness is actually different.

For example, 21Ga. corresponds to the standard steel thickness of 0.0329 inches (0.84mm); the corresponding galvanized steel thickness is 0.0366 inches (0.93mm), and the corresponding aluminum thickness is 0.028 inches (0.71mm).

For different metals, the same gauge value will correspond to different thickness values.

What thickness is 7 gauge?

Listed below are the inch thickness and mm thickness corresponding to 7 gauge.

Metals

7 Gauge

inch

mm

Steel

0.1793

4.5542

Galvanized Sheet

/

/

Stainless Steel

0.1875

4.7625

Aluminum

0.14428

3.66471

Brass

0.14428

3.66471

What thickness is 10 gauge?

Listed below are the inch thickness and mm thickness corresponding to 10 gauge.

Metals

10 Gauge

inch

mm

Steel

0.1345

3.4163

Galvanized Sheet

0.1382

3.5103

Stainless Steel

0.14063

3.57188

Aluminum

0.10189

2.58801

Brass

0.10189

2.58801

What thickness is 11 gauge?

Listed below are the inch thickness and mm thickness corresponding to 11 gauge.

Metals

11 Gauge

inch

mm

Steel

0.1196

3.0378

Galvanized Sheet

0.1233

3.1318

Stainless Steel

0.125

3.175

Aluminum

0.09074

2.30485

Brass

0.09074

2.30485

What thickness is 13 gauge?

Listed below are the inch thickness and mm thickness corresponding to 13 gauge.

Metals

13 Gauge

inch

mm

Steel

0.0897

2.2784

Galvanized Sheet

0.0934

2.3724

Stainless Steel

0.09375

2.38125

Aluminum

0.07196

1.82781

Brass

0.07196

1.82781

What thickness is 14 gauge?

Listed below are the inch thickness and mm thickness corresponding to 14 gauge.

Metals

14 Gauge

inch

mm

Steel

0.0747

1.8974

Galvanized Sheet

0.0785

1.9939

Stainless Steel

0.07813

1.98438

Aluminum

0.06408

1.62773

Brass

0.06408

1.62773

What thickness is 16 gauge?

Listed below are the inch thickness and mm thickness corresponding to 16 gauge.

Metals

16 Gauge

inch

mm

Steel

0.0598

1.5189

Galvanized Sheet

0.0635

1.6129

Stainless Steel

0.0625

1.5875

Aluminum

0.05082

1.29083

Brass

0.05082

1.29083

What thickness is 18 gauge?

Listed below are the inch thickness and mm thickness corresponding to 18 gauge.

Metals

18 Gauge

inch

mm

Steel

0.0478

1.2141

Galvanized Sheet

0.0516

1.3106

Stainless Steel

0.05

1.27

Aluminum

0.0403

1.0237

Brass

0.0403

1.0237

What thickness is 20 gauge?

Listed below are the inch thickness and mm thickness corresponding to 20 gauge.

Metals

20 Gauge

inch

mm

Steel

0.0359

0.9119

Galvanized Sheet

0.0396

1.0058

Stainless Steel

0.0375

0.9525

Aluminum

0.03196

0.81181

Brass

0.03196

0.81181

What thickness is 22 gauge?

Listed below are the inch thickness and mm thickness corresponding to 22 gauge.

Metals

22 Gauge

inch

mm

Steel

0.0299

0.7595

Galvanized Sheet

0.0336

0.8534

Stainless Steel

0.03125

0.79375

Aluminum

0.02535

0.64381

Brass

0.02535

0.64381

What thickness is 24 gauge?

Listed below are the inch thickness and mm thickness corresponding to 24 gauge.

Metals

24 Gauge

inch

mm

Steel

0.0239

0.6071

Galvanized Sheet

0.0276

0.701

Stainless Steel

0.025

0.635

Aluminum

0.0201

0.51054

Brass

0.0201

0.51054

What thickness is 26 gauge?

Listed below are the inch thickness and mm thickness corresponding to 26 gauge.

Metals

26 Gauge

inch

mm

Steel

0.0179

0.4547

Galvanized Sheet

0.0217

0.5512

Stainless Steel

0.01875

0.47625

Aluminum

0.01594

0.40488

Brass

0.01594

0.40488

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27 thoughts on “Sheet Metal Gauge Thickness Chart (Galvanized Sheet, Steel, Aluminum, Brass)”

  1. This is the best explanation of gauges I’ve ever seen. Just when I would think I understood this, I’d end up questioning everything all over again, which is how I ended up here. So, thank you for the “Okay, NOW I get it!” moment! Makes perfect sense why it made no sense before, because it’s subjective, like lots of other American empirical systems. Again, thanks so much!

  2. Thank you for the informative information.
    But surely the most logical solution is for the US & Canada to change to the metric system?

    The UK & Europe have been metricated since 1969.
    This would surely save a lot of messing around as there are different thickness for different materials with the same gauge.

  3. The US is metric, and has been since the beginning of the metric system. Prior to the invention of the metric system the world was in chaos, with dozens of strange and incompatible and incommensurable systems of measurement in use. None of them were well-defined. Many countries, including the United States, saw the need in both commerce and in science for a single well-thought-out system of measurement. It took a long time, (France began working on it before 1700) but eventually a far superior system of weights and measures was worked out and entered into by treaty.
    In 1875, an international agreement, known as the Convention of the Metre, set up well defined metric standards for length and mass and established permanent mechanisms [commitees] to recommend and adopt further refinements in the metric system. This agreement, commonly called the ‘Treaty of the Meter’ in the United States, was signed by 17 countries, including the United States.
    So it can be said with complete correctness that the United States has always been “metric.” (The one unresolved dispute is the American insistence on using “.” as a decimal mark, whereas the Europeans prefer a “,” .)
    Why, then, is the U.S. civilian population still using the inch-pound and statute mile systems of units, when the rest of the world, including the United Kingdom, has converted to metric? Because American businesses three generations ago didn’t want to go to the expense of re-tooling, the American people two generations ago believed rumors (that the metric system was a subversive European plot) instead of looking at the science, and their legislators were not willing to force the issue. Still, among scientists, the metric system is used almost exclusively. It is simply better. All the “English” units are now defined in terms of metric primary standards. So for the public it will take longer, but we will get there. Nobody is forced to do anything they don’t want to. Get used to it at your own pace, but familiarity with all systems now in use will be an advantage to you.

  4. So, if I follow you correctly regarding how Gauge originated, the reason that the thickness of a given Gauge of different metals varies is a result of the different physical properties of a given metal. That is, how much of a size reduction can be made in a given pass through a die. As gold is an extremely ductile metal, I would expect that for a given wire diameter the Gauge of a gold wire would be less than for the same given diameter of an iron wire. That is the numeric value of the Gauge thickness of a gold wire would be smaller than for an equivalent diameter iron wire because you can have a greater diameter reduction with gold wire for a given draw because it is much more ductile than iron. Am I following your logic correctly or have I gone astray somewhere?

    If the Gauge is determined by the number of pulls, wouldn’t that mean that the diameter of different steel alloy compositions for the same Gauge would vary or has the use of Gauge now separated from the number of draws and that for a type of material, such as iron or steel over a fairly broad alloy range, the same thickness is assigned a “standard” Gauge number, even if the reality was that it might require a significant difference in the number of draws to get to the same diameter?

    Also, is the starting diameter of a stock rod standard over different metals? If it is not, then what is a Gauge value of zero. That is, it hasn’t been drawn at all? If you don’t have a standard starting diameter, it would seem that the same Gauge number could correspond to vastly different thicknesses depending on the diameter of your starting stock.

    Sorry, I’m not trying to be picky, as this was an informative post. I just find it fascinating and want to make sure that I correctly understand how this scale was developed and used.

    Thanks,

    John

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