The thickness of a piece of leather affects its durability and flexibility, meaning it’s important for the informed consumer to have a general idea of leather thickness is and what types of products each range is used for. There are several ways to measure the thickness of leather, which we will explain below.
We most frequently refer to the thickness of leather in terms of “ounces.” This can be confusing because the term actually refers to a linear measurement as opposed to weight. In the leather industry, an ounce is 1/64 of an inch. So, if you have a piece of leather that is 8 ounces, it’s 8/64 of an inch. An easy reference point is to remember that a U.S. quarter is 4 ounces in thickness.
Hides can be through a splitting machine that can skive a piece of leather down to the desired measurement. But each animal is different and a hide can vary in thickness, so most of the time you’ll see each measurement presented as a range, such as 6-7 oz. The image below shows a conversion chart between ounces, irons, inches, and millimeters, as well as a visual representation of the measurement.
The Iron is an old, but still occasionally used standard for measuring the thickness of leather. It is most often seen in shoe manufacturing, especially in the UK, although the millimeter is a much more common measurement now. There are 48 irons in an inch, so each iron is a little larger than an ounce.
What are different thicknesses used for?
An average leather outsole on a shoe is around 12oz (9 irons) thick. A leather insole is typically around 14oz in thickness to accommodate the welt. A shoe upper is around 5oz on a typical dress/business shoe, and the lining is about 1oz.
Of course, these thicknesses often vary with the type of shoe, type of welt, and the type of leather used. Italian dress shoes are usually sleeker and thus use thinner leather in the soles and uppers. Blake stitched or bonded soles don’t require a thick insole like Goodyear welted shoes.
Bags are generally crafted from medium weight leather and can be anywhere from 3-7 ounces, depending on the desired weight and durability. Many bags are lined with pigskin or another thin layer of leather, which usually measures in at around 2 ounces.
The standard weight for a sturdy men’s belt is 7-8 ounces.
Most wallets, notebook covers, and billfolds are made with leather that is 2-4 oz. Heavy accessories like knife sheaths, hard-sided cases, and holsters are in the 7-9 oz range.