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.