Leather Weights and Measurements

Measuring Leather Thickness


There are several different ways to measure the thickness of leather.  In the United States, leather thickness is generally measured in ounces.  Countries that use the metric system will typically show thicknesses in millimeters.  Some old cobblers still use irons as the standard. Below is a conversion chart so you can compare the different types of measurements.  Below that, just because I love useless information, is an explanation for each unit of measurement.



You will see all over our site that we reference the ounce size of our leather for each product. The ounce is not a weight-based measurement; it correlates with thickness. If you look at this chart, you will see what I mean. Some people assume that the ounces must refer to the weight of a piece of leather, such as 1 square foot of leather. But that’s not the case. Leather can vary immensely in terms of actual weight/heaviness. It depends entirely on the type of leather used, how much dye is injected, how much oil the leather is holding, what type of animal hide, etc. So we’re not talking about heaviness here, we’re talking about linear thickness. Leather comes from an animal. Like all living creatures, there will always be some variations between the animals. This will explain why most leather is sold with a range of thickness.  That is why you will see our leathers described as 3-4 ounce or 8-9 ounce.  

Weighing Standards and History


Ounces:  As I said above, ounces have nothing to do with how much the leather weighs.  1 ounce of leather is equal to 1/64th of an inch. The terminology comes from the textile industry.  For years, the garment and textile industry has provided fabric measurements in weight, often ounces.  This is to give designers an idea of the density and thickness of the material, and is usually measured in ounces per square yard (oz/yd2). For example, a heavy weave of cotton canvas fabric, cut 1 yard x 1 yard square, might weigh 12 oz per square yard. A lighter cotton muslin fabric, cut 1 yard x 1 yard square, might weigh 5 oz per square yard. 

Textiles are made to a uniform thickness and density so 4 ounce denim is 4 ounce denim across the board.  Hides, however, are never uniform in thickness or density. A 4 ounce oil tanned cow will weigh and feel completely different than a 4 ounce sueded cow.  The terminology stuck though.  


Irons:  The term irons is a term not much used anymore.  An iron is equal to 1/48th of an inch. It is used by shoemakers, primarily in Europe, so you probably will not see it in the descriptions of leather products or hides.  It is a very old term that referred to plates of iron that were used to measure the thickness of leather used for various parts of the shoe. These plates were used by cobblers all over Europe to ensure consistency in shoe making.