Steel gauge chart

When using sheet metal to build your product, there is one term that you will always come across. That is the gauge metal. For instance, you will see something like 18 gauge sheet metal.

Closely related to this term is the sheet metal gauge chart. To get a better understanding of these terms, this article is going to reveal everything that you should know about steel gauge chart. At the end of it you will be in a position to know what to do with this chart when it comes to their real-life application.

Steel Gauge Definition and How it Works

A steel sheet gauge chart (sometimes spelled “gage”) is used to indicate the quality thickness of  a particular steel. It is imperative to note that as the gauge number increases, the steel thickness decreases.

Gauges are usually used to specify the thickness of a steel sheet. Gauges are neither standard nor metric, and therefore the values are independent of these measurement systems. And this is where a steel gauge chart comes in.

A  steel sheet gauge conversion chart is often used to determine the particular thickness of the sheet in inches or millimeters. For instance, 18 gauge steel, consistent with a gauge conversion chart, is 0.0478 inch or 1.214 millimeters. The gauge number “18” holds no relevance to the particular measurements.

Sheet metal thickness gauges for steel are fully based on the weight of 41.82 pounds per sq ft per inch of thickness. This is often referred to as the Manufacturers’ Standard Gage for Sheet Steel.

For other materials, like aluminum and brass, the thicknesses are going to be different. For instance, a 10 gauge steel sheet with a thickness of 0.1345 inches will weigh 41.82*0.1345 = 5.625 pounds per sq ft.

There are several different types of sheet metal gauge systems used today, with specific gauge designations used for specific metal types.

For instance, in one gauge system, 18 gauge steel measures 0.0478 inches thick, but 18 gauge aluminum is 0.0403 inches thick.

Due to the varying thicknesses, a gauge chart should be used to make sure the metal meets the specified dimensions.

History of Steel gauge chart

Sheet steel gauge chart draws its history back to the age of the industrial revolution. That was when metal sheets were used for various commercial activities.

There was a dire need for craftsmen and artisans to use accurate metal sheets so that the products can have physical and structural integrity. For instance, the diameter of the steel wires had to be quantified before being used.

One of the methods that were used for measuring the steel metal sheets was the gravimetric method. However, this method was quite hectic, especially when a buyer wanted a particular weight of steel sheet but did not specify the diameter.

It is at this point that artisans started denoting the metal sheets by their diameter vs. weight. From there, the steel gauge chart has been evolving up to the latest charts.

How to Measure Sheet Metal Gauge Thickness

The gauge of a sheet of metal is used to give an accurate reference to how thick the steel is. The higher the values on the gauge, the thicker the piece is in millimeters.

If you would like to seek out out what gauge your sheet is, measure its thickness employing a regular tape. Then, using a steel sheet gauge chart, you’ll match that thickness up with the acceptable numbered gauge of your product.

Step 1

Use tape to determine the thickness of your sheet piece. Use the millimeter hash marks to seek out the most accurate measurement possible.

Step 2

Multiply the number of millimeters by 0.03937 to convert to inches. If your measurement was 55 millimeters, for instance, you’d be left with 2.16535 inches.

Step 3

Compare the thickness of your sheet in inches to a sheet gauge chart to seek out the right gauge of that specific piece. For instance, if your sheet is 0.2391 inches, it might have a gauge of 3.

Why Know the Size of Steel Sheet?

As we have seen, steel metal sheet gauge will help you know the exact thickness of a steel sheet. But, what is the importance of this action?

One of the reasons is to minimize wastage of the metal sheet. You are aware that steel sheets are quite pricey hence you have to be very sparing when it comes to putting them into real applications.

By measuring the exact thickness, you will avoid using unnecessarily thicker steel sheets. This will in turn ensure that you don’t spend more money on the steel sheet.

Some sensitive applications require that you use the exact sizes of steel sheets. This will in turn reserve the quality and integrity of your product.

So, when dealing with any product, always remember to use the steel gauge chart to ascertain its size.

Factors to Consider when Determining Steel Sheet Sizes


While some people measure sheet thickness in millimeters, the ideal dimensions is in gauges. The larger the gauge number, the thinner the sheet. The smaller the gauge number, the thicker the sheet. The standards used to develop the gauge system were based on the weight of fabric in a specified size sheet.


The thickness of a steel sheet is one of the things to think about. This is vital not only due to the quality of the steel but also due to the labor required to cut the sheet.  Thicker sheets are harder to cut, and bends require sheets of roughly 1x or thicker than the radii of inside bends to avoid cracking or warping.


Every steel sheet of a selected gauge features a specific weight. In most cases, the weight is measured using pounds per sq ft. In some places and many other parts of the planet, the load is weighed in kilograms per square meter.

Tables of steel gauge charts

Stainless Steel Gauge Chart*
Inches MM
8 .17187 4.365
9 .15625 3.968
10 .14062 3.571
11 .125 3.175
12 .10937 2.778
14 .07812 1.984
16 .0625 1.587
18 .050 1.270
20 .0375 .9525
22 .03125 .7937
24 .025 .635
26 .01875 .476
28 .01562 .396
30 .0125 .3175


Galvanized Steel Gauge Chart*
Inches MM
8 .1681 4.269
9 .1532 3.891
10 .1382 3.510
11 .1233 3.1318
12 .1084 2.753
14 .0785 1.9939
16 .0635 1.6129
18 .0516 1.310
20 .0396 1.005
22 .0336 .853
24 .0276 .701
26 .0217 .551
28 .0187 .474
30 .0157 .398

Related source links:

Everything You Should Know About Stainless Steel Grades

Everything You Should Know About Stainless Steel Sheet Metal

Everything you should know about stainless steel mesh

Everything You Should Know About Stainless Steel Finishes

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