Processes - Sheet Metal

Gauge (or gage) sizes are numbers that indicate the thickness of a piece of sheet metal, with a higher number referring to a thinner sheet. The equivalent thicknesses differ for each gauge size standard, which were developed based on the weight of the sheet for a given material. The Manufacturers' Standard Gage provides the thicknesses for standard steel, galvanized steel, and stainless steel. The Brown and Sharpe Gage, also known as the American Wire Gage (AWG), is used for most non ferrous metals, such as Aluminum and Brass. In the UK, the Birmingham Gage (BG) is used for a variety of metals and should not be confused with the Birmingham Wire Gage (BWG), which is used for wires. Lastly, a standard exists for Zinc in which a higher gauge number indicates a thicker sheet. The chart below can be used to determine the equivalent sheet thickness, in inches or millimeters, for a gauge number from the selected gauge size standard. The weight per unit area of the sheet can also be seen in pounds per square foot and kilograms per square meter.