Sheet Metal Thickness Guide & Size Charts (Gauge, mm & Inches)

December 27, 2022
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Graham Dawe
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Whether you’re scouting for different sheet metals for commercial metal fabrication, knowing the standard thickness measurements and how they affect the final product is essential.

The standard thickness for sheet metals will vary depending on the type of metal. A sheet metal gauge chart uses the thickness and weight per area of different metals to determine standardised thicknesses or ‘gauges’. The higher the gauge, the thinner the sheet.

Selecting the correct thickness is a critical part of the sheet metal fabrication design process. That’s why we’ve created this handy guide.

In this article, you’ll find gauge and size charts for common sheet metal types, as well as some background information on how sheet metal is measured.

If you are keen to learn more about sheet metal size and thickness, read on!

Table of Contents

What is the Standard Thickness of Sheet Metal?

In Australia, the typical thickness of sheet metal is between 0.5 millimetres and 6 millimetres. Anything thicker 6 millimetres is classified as metal plate, and anything thinner than 0.5 millimetres is classified as metal foil.

The thickness of metal foil, sheet, and plate is measured in millimetres, mils, and gauges. People will likely only be familiar with millimetres, as mils and gauges are used almost exclusively within the manufacturing and engineering industries. In this scenario, ‘mils’ doesn’t stand for ‘millimetres’ – it’s a different measurement referring to a thousandth of an inch, which can be confusing.

There are different ‘standard thicknesses’ for every type of metal, from 0.5 to 50 millimetres. However, remember that once the thickness exceeds 0.6 millimetres, the classification changes from sheet metal to metal plate.

Stainless Steel Sheet Thickness Chart

Gauge	Thickness (inches)	Thickness (mm)
7	0.1875	4.76
8	0.1719	4.37
9	0.1563	3.97
10	0.1406	3.57
11	0.1250	3.18
12	0.1094	2.78
13	0.094	2.4
14	0.0781	1.98
15	0.07	1.8
16	0.0625	1.59
17	0.056	1.4
18	0.0500	1.27
19	0.044	1.1
20	0.0375	0.95
21	0.034	0.86
22	0.031	0.79
23	0.028	0.71
24	0.025	0.64
25	0.022	0.56
26	0.019	0.48

Stainless steel is tough but relatively lightweight and versatile enough for many applications. The term ‘stainless steel’ refers to a group of iron-based metal alloys comprising around 10.5% chromium. This additive is responsible for resisting corrosion by forming a very thin layer on the surface of the steel.

Several types of stainless-steel sheets are available and used in many applications, such as aerospace, architecture, construction, chemical industries, water and waste processing, science laboratories, nuclear power plants, energy, and pharmaceuticals.

Standard Steel Sheet Thickness Chart

Gauge	Measurement (inches)	Thickness (mm)
3	0.2391	6.073
4	0.2242	5.695
5	0.2092	5.314
6	0.1943	4.935
7	0.1793	4.554
8	0.1644	4.176
9	0.1495	3.797
10	0.1345	3.416
11	0.1196	3.038
12	0.1046	2.657
13	0.0897	2.278
14	0.0747	1.897
15	0.0673	1.709
16	0.0598	1.519
17	0.0538	1.367
18	0.0478	1.214
19	0.0418	1.062
20	0.0359	0.912
21	0.0329	0.836
22	0.0299	0.759
23	0.0269	0.683
24	0.0239	0.607
25	0.0209	0.531
26	0.0179	0.455
27	0.0164	0.417
28	0.0149	0.378
29	0.0135	0.343
30	0.0120	0.305
31	0.0105	0.267
32	0.0097	0.246
33	0.0090	0.229
34	0.0082	0.208
35	0.0075	0.191
36	0.0067	0.170
37	0.0064	0.163
38	0.0060	0.152

Standard steel is usually categorised into hot and cold rolled steel. The former is rolled at high temperatures, while the latter is rolled at the same high temperature but with further processing involving cold reduction materials.

Hot rolled steel usually has a scaly finish with slight distortions but is very malleable and ductile without compromising strength. It is much cheaper than cold-rolled steel, is used to create structural components (such as railroad tracks), and is used in metal buildings, automotive frames, and agricultural equipment.

Hot rolled steel, on the other hand, can achieve more surface finishings due to the added processing. It generally has a smooth surface that may feel ’oily’ when touched. It is usually seen in precise applications and is much stronger than hot-rolled steel. Commonly used in home appliances, automotive parts, metal furniture, and aerospace components.

Galvanised Steel Sheet Thickness Chart

Gauge	Thickness (inches)	Thickness (mm)
8	0.1681	4.27
9	0.1532	3.89
10	0.1382	3.51
11	0.1233	3.13
12	0.1084	2.75
13	0.0934	2.37
14	0.0785	1.99
15	0.0710	1.80
16	0.0635	1.61
17	0.0575	1.46
18	0.0516	1.31
19	0.0456	1.16
20	0.0396	1.01
21	0.0366	0.93
22	0.0336	0.85
23	0.0306	0.78
24	0.0276	0.70
25	0.0247	0.63
26	0.0217	0.55

Galvanised steel sheets are metal sheets that have undergone an extensive fabrication process in order to enable them to be flattened and coated with a layer of molten zinc metal for added protection. The applications for such sheet metals range from decorative/aesthetic fixtures to the construction industry.

Among the primary applications for these are automotive parts due to their resistant Zinc coating and home/kitchen appliances such as kitchen trays, microwaves, and toasters. For heavier use, these sheet metals are used to create metal fittings, particularly for construction purposes.

Aluminium Sheet Thickness Chart

Gauge	Thickness (inches)	Thickness (mm)
6	0.162	4.1
7	0.1443	3.67
8	0.1285	3.26
9	0.1144	2.91
10	0.1019	2.59
11	0.0907	2.30
12	0.0808	2.05
13	0.072	1.8
14	0.0641	1.63
15	0.057	1.4
16	0.0508	1.29
17	0.045	1.1
18	0.0403	1.02
19	0.036	0.91
20	0.0320	0.81
21	0.028	0.71
22	0.025	0.64
23	0.023	0.58
24	0.02	0.51
25	0.018	0.46
26	0.017	0.43

Aluminium sheet metal is among the most widely used sheet metal materials today, mainly because of its versatility. Aluminium is light, resistant to corrosion, and pliable enough to be worked into a wide range of shapes.

Aluminium sheet metal is often seen in the packaging industry, particularly for food and beverages. Canned goods and lightweight drink cans are the principal end product.

The primary reason for its popularity is its immunity toward rust, which also gives the material applications in automobile bodies, appliances, cookware, and even the construction sector.

Zinc Sheet Thickness Chart

Gauge	Thickness (inches)	Thickness (mm)
1	0.0020	0.051
2	0.0040	0.102
3	0.0060	0.152
4	0.0080	0.203
5	0.0100	0.254
6	0.0120	0.305
7	0.0140	0.356
8	0.0160	0.406
9	0.0180	0.457
10	0.0200	0.508
11	0.0240	0.610
12	0.0280	0.711
13	0.0320	0.813
14	0.0360	0.914
15	0.0400	1.016
16	0.0450	1.143
17	0.0500	1.270
18	0.0550	1.397
19	0.0600	1.524
20	0.0700	1.778
21	0.0800	2.032
22	0.0900	2.286
23	0.1000	2.540
24	0.1250	3.175
25	0.2500	6.350
26	0.3750	9.525
27	0.5000	12.700
28	1.0000	25.400

Zinc sheets were initially created for industrial applications such as chemical resistance, water resistance, cathode protection, engraving, roof flashing, sound deadening, and other scientific applications. As time passed, the applications for zinc sheets expanded and rapidly gained popularity in commercial applications, among which were cabinet tops and bar finishes.

This material has also recently been used in decorative applications in certain architectural designs. For instance, zinc tables are considered attractive in France. Nowadays, you can also see this material used in food-grade applications such as stove enclosures, kitchen cooking areas, and sink tops.

Copper Sheet Metal Thickness Chart

Gauge(Birmingham Gauge Standard B.W.G.)	Thickness (inches)	Thickness (mm)
10	0.1250	3.175
12	0.1080	2.7432
13	0.0930	2.3622
14	0.0863	2.19202
15	0.0750	1.905
16	0.0647	1.64338
18	0.0485	1.2319
19	0.0430	1.0922
21	0.0320	0.8128
22	0.0270	0.6858
24	0.0216	0.54864
27	0.0160	0.4064
28	0.0135	0.3429
31	0.0108	0.27432
36	0.0050	0.127

Copper sheets are known to have high electrical conductivity, heat capacity, antimicrobial properties, corrosion resistance, malleability, and ductility. These properties have turned copper sheets into a preferred material for welding fixtures, ground straps (machines that protect people and components from electrostatic discharges), plumbing fittings (due to their corrosion resistance), power transmission (sprockets, belt pulleys, sheaves, and bushings are often made from copper), as well as heat exchangers (due to its high heat capacity).

Brass Sheet Thickness Chart

Gauge(Brown & Sharpe’s Gauge Standard B & S/ American Gauge A.W.G.)	Thickness (inches)	Thickness (mm)
11	0.090	2.286
12	0.081	2.0574
14	0.063	1.6002
16	0.050	1.27
18	0.040	1.016
20	0.032	0.8128
22	0.025	0.635
24	0.020	0.508
26	0.016	0.4064
28	0.013	0.3302
30	0.010	0.254

Brass is an alloy containing zinc and copper and is usually identifiable by its relatively yellow colour. The ratio of zinc and copper differs depending on preferred properties and the material’s intended application.

Copper is durable and resistant to corrosion, which makes it a favoured material for tools (such as hammers used for delicate steel components), musical instruments (due to its tonal quality), and technology (for its high electrical conductivity).

What is Gauge in Sheet Metal Fabrication?

In the fabrication industry, ‘gauge’ is an identifier for the standard thickness of sheet metal of a specific material. The gauge size is based on the weight of the metal sheet and is inversely proportional to the thickness, which means the higher it is, the thinner the sheet metal is.

Gauges do not fall under imperial or metric measurement systems. Although the gauge numbers correspond to a certain measurement, different sheet metal materials with the same gauge number will not have the same thickness because the gauge holds no actual bearing on the measurements. For instance, a 16-gauge aluminium will measure 1.29 millimetres, while a 16-gauge stainless steel will measure 1.59 millimetres.

The gauge system has a long history in the metal fabrication industry and likely originated from the British wire industry prior to the creation and widespread adoption of modern measurement systems. Although gauges initially began as a way to measure the diameter of a metal wire, it has been retained as a way to measure metals of varying thicknesses, including sheet metal.

How to Measure Sheet Metal Thickness?

There are two ways to measure sheet metal: using a measuring tape (which is less precise) and a gauge wheel (more typically used in the industry).

1. Using a measuring tape

First, grab a measuring tape and look for the millimetre hash. Although you may measure using centimetres, it will not be able to provide you with precise measurements. Place your measuring tape perpendicular to the sheet metal so you can measure its thickness correctly.

After obtaining the measurement in millimetres, you can convert it to inches by multiplying the value in millimetres by 0.03937. After you obtain either measurement, compare the value with those on a sheet metal gauge of the appropriate material to accurately identify the gauge.

2. Using a gauge wheel

Gauge wheels come in two variations, one for nonferrous metals (without iron) and one for ferrous metals (with iron). You can identify your gauge wheel type by reading the label on the wheel itself.

The gauge wheel has gaps with corresponding numbers; place the sheet metal into the gaps until you find one where it fits perfectly. Note that the gap you should be looking at is the flat one, not the rounded inner gap. After you identify the gap where it perfectly fits, check the corresponding number, it should show the gauge of the sheet metal.

What are the Most Common Sheet Metal Sizes?

Aside from the thickness of the sheet metals, they also come in different sizes. Although there is a range of standard sheet metal sizes, the most common ones are 36”x 96”, 36”x 120”, 36”x 144”, 48”x 96”, 48”x 120”, and 48”x 144”.

While sheet metal thickness/gauge number has a corresponding weight ratio, such as lbs per square foot or kilograms per square metre, sheet metal sizes are not tied to the thickness. This means you may purchase an 18-gauge metal sheet in several different sizes, depending on your needs and use.

Is it Important to Know My Sheet Metal Thickness?

Yes, sheet metal thickness is important as it determines what kind of fabrication processes can be used. Thinner sheet metal is suitable for different processes and different applications to thicker sheets. Therefore, knowing the required thickness is critical to the design process.

Some would even argue that the thickness of sheet metal is its most important parameter since it directly influences the material’s constraints and temperature gradient. Other processes that are influenced by the thickness include stretching, bending, and straightening.

How Do You Choose Sheet Metal Thickness?

Choose sheet metal thickness based on the application and the metal. For instance, if you are going to use a very flexible sheet metal material for an application that requires it to be sturdy, choosing a thicker sheet metal would offset the flexibility while retaining the metal’s unique properties.

It is important to understand that sheet metal thickness is not the only factor to be considered and that the relation of all parameters – thickness, size, metal/material properties, and application/usage – must be considered.

This is why proper sheet metal project design and modelling for metal fabrication is so important, to ensure that the final product will look and behave as intended using specific sheet metals.