Glossary
Leather weight (oz)
The thickness of leather measured in ounces, where each ounce equals about 1/64 inch or roughly 0.4 mm of thickness.
Leather weight tells you how thick a hide is, expressed in ounces rather than inches or millimeters. Each ounce adds about 1/64 inch, so 4 to 5 oz leather runs around 1.6 to 2 mm thick, while a heavy 9 to 10 oz hide is closer to 3.6 to 4 mm. Suppliers usually list a range like 4 to 5 oz rather than a single number, since natural hides vary slightly across their surface.
The right weight depends entirely on the project. Wallets and card holders want thin, flexible leather in the 2 to 4 oz range so folds stay slim and stitching is easy to pull through by hand. Belts, bags, and holsters need something in the 7 to 10 oz range for structure and durability, and some strap work goes even heavier. Using the wrong weight is one of the most common reasons a first project feels stiff, floppy, or impossible to stitch.
When buying, check whether a listing gives a single weight or a range, and remember that veg-tan and chrome-tan of the same stated ounce weight can still feel different in hand because of how each is tanned and finished. If you plan to skive or fold an edge, start slightly heavier than you think you need, since skiving removes material and thin leather leaves little room for error.