Leather Thicknesses...... Where to start??
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So you're starting a new project - a wallet, a belt, a watch strap - and you've hit one of the first big decisions: what thickness of leather to use. Too thin, and the piece can stretch or wear out before its time. Too thick, and it fights you at every fold and stitch. I learned this one the hard way early on, ruining more than one project because I'd picked the wrong weight of leather for the job. Once you get a feel for how thickness affects strength, flexibility, and look, the choice gets a lot less mysterious.
This post breaks the common leather thicknesses down into bands, and what I'd actually use each one for.
Understanding Leather Thickness
Leather thickness is typically measured in ounces (oz) or millimeters (mm).
1 oz ≈ 0.4 mm
Leather usually ranges from 1 oz (0.4 mm) to 16 oz (6.4 mm)
Higher ounce leather is thicker, stiffer, and more durable. Lower ounce leather is thinner, softer, and more flexible.
Thin Leather (1–3 oz / 0.4–1.2 mm)
Best used for these projects:
i) Wallet interiors
ii) Lining leather
iii) Watch straps
iv) Book covers
v) Lightweight pouches
vi) Garment leather
Why use this thickness?
I reach for this when I need something that folds, stitches, and layers without adding bulk. It's ideal for anything that needs flexibility or several layers glued together.
Things to Consider:
On its own it doesn't have much structure or durability. I usually back it with something heavier or add reinforcement.
Medium-Light Leather (3–5 oz / 1.2–2.0 mm)
Best used for these projects:
i) Wallet exteriors
ii) Card holders
iii) Small bags and clutches
iv) Notebook covers
v) Soft belts
vi) Camera straps
Why use this thickness?
This is my go-to middle ground between strength and flexibility - thick enough to hold its shape but still thin enough to hand stitch and fold comfortably.
Things to Consider:
At stress points, like belt holes or strap ends, I'll often add reinforcement or double up the layers.
Medium Leather (5–7 oz / 2.0–2.8 mm)
Best used for these projects:
i) Belts
ii) Tote bags
iii) Tool rolls
iv) Knife slips
v) Structured handbags
vi) Sandals
Why use this thickness?
This is one of the most versatile ranges I use - strong and durable, but still workable with hand tools.
Things to Consider:
Edges often need bevelling and burnishing to cut down on bulk, especially anywhere there's a fold.
Medium-Heavy Leather (7–9 oz / 2.8–3.6 mm)
Best used for these projects:
i) Heavy-duty belts
ii) Sheaths
iii) Satchels
iv) Backpack panels
v) Work aprons
Why use this thickness?
Thicker leather gives you real durability and structure - good for anything that has to take weight, friction, or repeated use.
Things to Consider:
Stitching gets harder at this thickness. I pre-punch every hole and use stronger needles and thread.
Heavy Leather (9–12 oz / 3.6–4.8 mm)
Best used for these projects:
i) Holsters
ii) Armor and cosplay pieces
iii) Saddlery components
iv) Heavy straps
v) Protective gear
Why use this thickness?
This is extremely strong and rigid leather - maximum protection and longevity.
Things to Consider:
You need heavy-duty tools and strong stitching technique here, and often wet-forming to shape it properly.
Extra-Heavy Leather (12–16 oz / 4.8–6.4 mm)
Best used for these projects:
i) Saddle skirts
ii) Soles (when stacked or compressed)
iii) Industrial leatherwork
iv) Historical armor
Why use this thickness?
This thickness is built for extreme strength and structure.
Things to Consider:
Not something I'd hand a beginner. Cutting, shaping, and stitching at this weight takes specialised tools and experience.
Quick Reference Table
| Project Type | Recommended Thickness |
|---|---|
| Wallet interiors | 1–2 oz (0.4–0.8 mm) |
| Wallet exteriors | 3–4 oz (1.2–1.6 mm) |
| Belts | 7–9 oz (2.8–3.6 mm) |
| Bags & totes | 4–7 oz (1.6–2.8 mm) |
| Sheaths & holsters | 8–10 oz (3.2–4.0 mm) |
| Watch straps | 2–4 oz (0.8–1.6 mm) |
| Armor & heavy gear | 10–16 oz (4.0–6.4 mm) |
Final Thoughts
Honestly, there's no single "right" leather thickness - only the right thickness for your project. I still get the odd one wrong, and most of what I know here I've picked up from mistakes rather than getting it right first time. When in doubt, think about structure, flexibility, and where the stress points are. I often combine two thicknesses in one piece to get the balance right - a heavier body with a lighter lining, say. Keep those things in mind when you're planning a project and the rest tends to fall into place.