Unless you do Leatherwork yourself, you have probably never heard of the term Leather Weight. But choosing the right weight of leather for your project is such an important part of creating any leather goods. The term “Leather Weight refers to the thickness of your leather; leather thickness is generally measured in ounces in North America thus the term “Leather Weight”.

Leather weight or thickness has been measured with gauges in different units around the world across different industries, in general, you can find leather measured in three different units:

• Thickness (mm or inches)
• Weight (oz)
• Irons

Weight is the most commonly used unit in North America. Because leather is a natural product its thickness across the entire width of a hide can vary. Variations in the thickness can be caused by many different factors, such as scars and imperfections, how the hides are split, and the chemical process used during tanning. while all of this is normal and unavoidable there had to be some kind of standard that could be recognized across the industry, as such a single piece of leather is often ratted in ranges such as 2-3oz.

Take a look at this handy chart for the different weight-to-thickness conversions:📊

Ounces:	Inches:	Inches (Decimal):	Millimeters:	Irons:
1oz	1/64″	0.0157	0.40	0.75
2oz	1/32″	0.0313	0.80	1.50
3oz	3/64″	0.0469	1.20	2.25
4oz	1/16″	0.0625	1.60	3.00
5oz	5/64″	0.0781	2.00	3.75
6oz	3/32″	0.0938	2.40	4.50
7oz	7/64″	0.1094	2.80	5.25
8oz	1/8″	0.1250	3.20	6.00
9oz	9/64″	0.1406	3.60	6.75
10oz	5/32″	0.1563	4.00	7.50
11oz	11/64″	0.1719	4.40	8.25
12oz	3/16	0.1875	4.80	9.00

Weight (oz):

Leather weight in (oz) is the most common unit of measure for leather in North America and relates to the textile industry. As the garment and textile industry has been providing fabric measurements in weight and often in ounces; this is to give designers an idea of the density and thickness of the fabric.

In the textile industry, the weight of a fabric oz is calculated by cutting a square piece 1-yard x 1-yard and weighing it in oz. For example, the canvas liner I like to use in my bags is a thick heavy-duty canvas that is gauged at 12oz so a piece 1-yard by 1-yard square of this fabric would weigh 12oz.

in the case of leather, because it is a denser, thicker material than most fabrics the calculation for its weight uses a 1-foot x 1-foot square of material instead. Using this smaller square size allows the scale to start at a smaller oz measurement such as 1oz.

When converting leather weight to thickness in inches: 1oz of leather is equivalent to 1/64″. For example, an 8oz piece of leather would be 8/64″ thick or 1/8″.

Thickness (Millimeters):

The most popular unit of measurement for leather thickness around the world is the millimeter (mm). It is a metric unit of measure used around the world and is popular when measuring Leather as there are no conversions required. A 0.2mm thick piece of leather is 0.2mm. Because it is the most popular standard of measurement around the world it is commonly understood and doesn’t require any explanation or additional equations.

Irons:

An older unit of measurement for leather that is generally used by cobbles in shoemaking is irons. the shoe soles and various other leather parts in shoemaking are measured in Irons. it is not very common nowadays in leatherworking altho you can still find it in use with those who are familiar with it and is still considered a valid unit of measure. when converting Irons to thickness in inches: 1 Iron is equivalent to 1/48″. for example a 1/8″ thick piece of leather would be 6/48″ or 6irons thick

When developing the iron standard as a unit of measure, it is thought that pieces of actual iron of uniform thickness were used. This would have helped to ensure that leather thicknesses around the world matched and that everyone could rely on their accuracy and potentially double-check stated thicknesses if they had a set or irons themselves.

Why should you care?

With all the different thicknesses available it is important to know what each thickness is generally used for, the heavier the leather, the stiffer it will be, and the lighter the leather the more flexible and malleable it will be. Basically, the heavier leather will hold a shape and can be carved, molded, or stand up; the lighter leather will be more drapey.

For example, a bag made from a heavier weight of leather when put down will remain standing and keep its shape, while a bag made from lighter leather will pool or fold when put down.

when creating a custom leather good it is important that you know and understands how different weights of leather will act for your project as some might be better suited than others, however different weights of leather can completely change both the look and feel of your leather goods.

Take a look at this chart for the different weight ranges and their most common uses: