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

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!

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 

GaugeThickness (inches)Thickness (mm)
70.18754.76
80.1719 4.37
90.15633.97
100.14063.57
110.12503.18
120.10942.78
130.0942.4
140.07811.98
150.071.8
160.06251.59
170.056 1.4
180.05001.27
190.0441.1
200.03750.95
210.0340.86
220.0310.79
230.028 0.71
240.0250.64
250.0220.56
260.0190.48

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

GaugeMeasurement (inches)Thickness (mm)
30.23916.073
40.22425.695
50.20925.314
60.1943 4.935
70.17934.554
80.16444.176
90.14953.797
100.13453.416
110.11963.038
120.10462.657
130.08972.278
140.07471.897
150.06731.709
160.05981.519
170.05381.367
180.04781.214
190.04181.062
200.03590.912
210.03290.836
220.02990.759
230.02690.683
240.02390.607
250.02090.531
260.01790.455
270.01640.417
280.01490.378
290.01350.343
300.01200.305
310.01050.267
320.00970.246
330.00900.229
340.00820.208
350.00750.191
360.00670.170
370.0064 0.163
380.00600.152

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

GaugeThickness (inches)Thickness (mm)
80.1681 4.27
90.1532 3.89
100.13823.51
110.12333.13
120.10842.75
130.0934 2.37
140.0785 1.99
150.0710 1.80
160.06351.61
170.05751.46
180.05161.31
190.04561.16
200.03961.01
210.03660.93
220.03360.85
230.03060.78
240.02760.70
250.02470.63
260.02170.55

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 

GaugeThickness (inches)Thickness (mm)
60.1624.1
70.14433.67
80.12853.26
90.11442.91
100.10192.59
110.09072.30
120.08082.05
130.0721.8
140.06411.63
150.0571.4
160.05081.29
170.0451.1
180.04031.02
190.0360.91
200.03200.81
210.0280.71
220.0250.64
230.0230.58
240.02 0.51
250.0180.46
260.0170.43

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 

GaugeThickness (inches)Thickness (mm)
10.00200.051
20.00400.102
30.00600.152
40.00800.203
50.01000.254
60.01200.305
70.01400.356
80.01600.406
90.01800.457
100.02000.508
110.02400.610
120.02800.711
130.03200.813
140.0360 0.914
150.0400 1.016
160.04501.143
170.05001.270
180.05501.397
190.06001.524
200.07001.778
210.08002.032
220.09002.286
230.10002.540
240.12503.175
250.25006.350
260.37509.525
270.500012.700
281.000025.400

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)
100.1250 3.175
120.10802.7432
130.09302.3622
140.0863 2.19202
150.07501.905
160.06471.64338
180.04851.2319
190.04301.0922
210.03200.8128
220.02700.6858
240.0216 0.54864
270.01600.4064
280.0135 0.3429
310.0108 0.27432
360.00500.127

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)
110.0902.286
120.0812.0574
140.0631.6002
160.0501.27
180.0401.016
200.0320.8128
220.025 0.635
240.020 0.508
260.0160.4064
280.0130.3302
300.010 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.

Related Questions

Does Sheet Metal Stretch When Bent?

Yes, sheet metal stretches in length when bent. The amount of stretch it goes through is referred to as the bend deduction and is measured from the outside edges of the bend. On the other hand, the bend radius refers to the inside radius. It depends on the sheet metal’s properties and thickness.

What is Bend Allowance?

Bend allowance is the material that must be added to the total length of the sheet metal to ensure that it gets cut at the right size or in a flat pattern. This value is identified using a formula, which requires the values for the sheet metal’s thickness, bend angle, inside radius, and the K-Factor.

Disclaimer:

This article is published in good faith and for general informational purposes only. Kanyana Engineering does not make any warranties about the ongoing completeness and reliability of this information. Always seek specific advice on your metal fabrication project to ensure all variables are taken into consideration.