Leather Weight Guide
The term "weight" means thickness when describing leather. Leather thickness and weight go hand in hand. The "weight" or "thickness" of the leather are described per square foot. One square foot of 3/4oz leather will usually weigh about 3-4 ounces, one square foot of 4/5oz leather will usually weigh around 4-5 ounces and so on. A 3/4 oz piece of leather would measure to around 1.2-1.6mm thick.
Another thing to remember is that leather is almost always gauged in a range of thicknesses. That's why it is called 3/4oz and not just 3oz. Leather is a natural material that can vary in thickness over the area of the hide. One side might be slightly thicker or thinner than the other.