How to differentiate sheet vs plate

What is the Difference between Sheet, Plate, and Foil?

Aluminum sheet and aluminum plate are both widely used and respected due to the metal’s light-weight strength, along with high corrosion resistance. But what is the difference between sheet, plate, and foil?

When choosing between the three types of products, the only difference is the thickness – with plate being thickest and foil the thinnest. However, the exact thicknesses separating the categories depend upon the application, the metal in question, the gauge, and product specifications.

Independent & Inconsistent Metal Standards

Historically, gauges were the standards used to specify the thickness of metal wires before new, more accurate measurement technology was developed. Each industry created its own standards independently, and as a result, gauge numbers vary for aluminum, copper, brass, and different types of steel.

For example, the Dictionary of Units of Measurement defines 10 gauge aluminum as being 0.1019 inches thick, while 10 gauge standard steel is 0.1345 inches and a 10 gauge galvanized steel is 0.1382 inches.

As a result of this confusing state of affairs, the American Society for Testing and Measurement (ASTM) says in specification ASTM A480-10a, ‘The use of gage number is discouraged as being an archaic term of limited usefulness not having general agreement on meaning.’

Modern Metal Thickness Measurements

The common practice today is to specify the exact thickness of the product in question, thought the gauge may also be listed. In the case of aluminum and its alloys, sheet is typically defined as a piece of metal that is less than 0.249 inches thick. Aluminum plate is 0.25 inches and thicker, while aluminum foil is defined as anything thinner than 0.006 inches.

Due to their superior physical properties, aluminum sheet and plate are sought after for many different industrial applications. Aluminum plate is used for heavy-duty and structural applications, such as aerospace, military, and rail and sea transportation.

Aluminum sheet is the most common form of the metal, and is used in a wide range of industries, from food & beverage canning to cookware, appliance, and auto manufacturing. It is especially useful for construction of roofing, gutters, and siding.

Contact Industrial Metal Supply for your aluminum sheet & plate needs, or if you have questions.

Measuring Metal Thickness

In today’s metal industry, gauge and inch measurements are both used to describe thickness. Below, we’ve outlined the distinctions between each method.


When purchasing sheet metal, the thickness is typically measured via the gauge system. Unlike other measurements, gauges are not linear. Instead, as the gauge number goes up, the metal gets thinner. Depending on the metal, gauges are also different for ferrous and non-ferrous varieties, such as copper (measured in ounces). The measurement is abbreviated with the letters “ga”.

There are a few different gauge standards, including the Manufacturers’ Standard Gauge, which measures the thickness of regular, galvanized, and stainless steel. Meanwhile, the Brown and Sharpe Gauge is used to measure brass, aluminum, and other non-ferrous metals.


On the other hand, this measurement is pretty self-explanatory. If you grew up in the United States, you should be familiar with the Imperial system; if you’re from almost anywhere else in the world, it might be confusing at first. Essentially, one inch is equal to 25.4 millimeters, or 0.0254 meters. To put things into perspective, the largest gauge for standard sheet metal is called 0000000, and it is equal to 0.5 inches. On the smaller side, 7 gauge sheet metal equals approximately 0.1875 inches.

With that being said, it’s best to use gauges and inches in tandem when buying materials for a project. If you have experience in construction or metalworking, gauges offer a quick reference point, but they’re not the most coherent form of measurement. This makes inches helpful, so you can compare the two numbers side by side and then make a determination.