I keep this chart handy for myself and thought I would share it with all of our readers. Converting between oz, mm, and inch can be a pain, and this reference chart makes it a lot easier.
Most leather in the US is measured in ounces, and one ounce equals 1/64 of an inch. Remembering the inch-to-ounce conversion is a little easier if you halve the bottom of the fraction on every even ounce – so 2 oz. equals 1/32, 4 oz. equals 1/6, 8 oz. equals 1/8., etc.
An easy-to-remember conversion pair is 8 oz. equals 1/8.”
Many online stores, including ourselves, import leather from overseas, which is often measured in millimeters. 0.4 millimeters equals one ounce. Converting millimeters to ounces is simply dividing the millimeters by 0.4.
Millimeters / 0.4 = Ounces
| oz | millimeters | inch fractions | inch decimal |
|---|---|---|---|
| 1 | 0.4 | 1/64 | 0.0156 |
| 2 | 0.8 | 1/32 | 0.0313 |
| 3 | 1.2 | 3/64 | 0.0469 |
| 4 | 1.6 | 1/16 | 0.0625 |
| 5 | 2 | 5/64 | 0.0781 |
| 6 | 2.4 | 3/32 | 0.0938 |
| 7 | 2.8 | 7/64 | 0.1094 |
| 8 | 3.2 | 1/8 | 0.1250 |
| 9 | 3.6 | 9/64 | 0.1406 |
| 10 | 4 | 5/32 | 0.1563 |
| 11 | 4.4 | 11/64 | 0.1719 |
| 12 | 4.8 | 3/16 | 0.1875 |
| 13 | 5.2 | 13/64 | 0.2031 |
| 14 | 5.6 | 7/32 | 0.2188 |
| 15 | 6 | 15/64 | 0.2344 |
| 16 | 6.4 | 1/4 | 0.2500 |
The listed thickness of a hide online usually indicates the average thickness. Leather hides vary in thickness from the belly to the bend to the shoulder. When selecting a hide, remember to account for the natural thickness variation. Lastly, thickness is only one consideration when selecting what leather to use. For example, cutting a 12oz belt strip from the stretchier belly will be very different than cutting from the sturdier back of the hide.
Thank you for sharing this vital information with me. It will be of great value when I am making online purchases or even shopping in our local stores here. Thanks for keeping me informed
Thanks, as always, for reading Clarence! Glad this post could be of some benefit to you.
Thanks Clarence, important information to have at the ready.
Hi Sean,
What a brilliant and useful idea! Thanks ever so much for this handy chart.
I printed it out and laminated it for my work room wall above my desk.
All the best.
Paul.
Awesome, Paul! Glad you got some good use out of it.
New (a year or two) to leatherworking after a good chunk of the early 2000’s slogging time and too much money (but such cool project potentials) into PMC; For being ‘just’ sintered metal, one can throw down some really great and fun (but again, $pendy) craft-from-the-hands. This chart was very helpful today making my first non-plastic sheath and getting MM equiv’s for ounces, i can probably finally wrap a small carving knife up. +1 subscribed/following…warm winds to you and yours and keep on the creatin’!
Glad to hear! I’d love to see some photos of your work if you ever feel like sharing. Send us an email!
Que gran ayuda la de esta tabla, comencé relativamente hace poco a trabajar el cuero y el tema es que no tenía muy claro el tema cuando hablaban de onzas, ahora sí!…está tabla es una gran bendición, gracias.
I’m glad that you found this post useful. Thanks for taking the time to read!
Useful guide, thanks for posting.
I was taught to measure leather in irons but I guess it isn’t used anymore outside of traditional saddlery or Goodyear welted footwear. Fwiw I think 3/4 irons was about 1oz.
Glad we could be of some help, Mike. Thanks for reading!
Thank you for this list.
Thanks for taking a look, Mike!
I’m an octogenarian somewhat damaged by the years and now learning leatherwork from our little farm. I really appreciate this chart.
It’s an honor to have you here, John! Thanks for taking the time to read through our blog and respond. Keep in touch.
Thank you. This will be very useful.
Glad you found it helpful, Thomas!
Thank Yoiu. Been working with leather for about six years and still getting mixing that data up. 🙂
Glad this was helpful, Kamil!
Hola. Soy de Córdoba, Argentina. Aquí usamos de medida el mimímetro (mm) pero en muchas publicaciones es común que lo hagan en Onzas. No utilizar el espesor adecuado en un proyecto me resultó no lograr un buen trabajo. Muy útil como muchos artículos de FineLeatherWorking. Gracias
Gracias por leer nuestra publicación de blog y me alegra saber que este artículo fue útil para usted. ¡Mantenerse en contacto!