PCB design best practices

Copper thickness: Closing the knowledge gap to design success

Copper thickness determination of rolled and electro-deposited (ED) copper foil by weight provides far more accuracy than contact-thickness gauges. Since the topography of treated foil varies greatly, and since the density of copper is known, weighing a 1-by-1 foot sheet is the best way to determine the average thickness of a sheet of copper.  So formally, the unit that we refer to as “ounces” is actually ounces per square foot.