Hides · Reference table · 3 min read

Hide Weight: What Ounces Mean and When They Stop Working

Leather is sold by weight per square foot in the United States and by thickness in millimetres almost everywhere else, and the conversion is not exact — a 4/5 oz hide is not a fixed 1.8 mm, it is a range the tannery sorts into. Sorting matters more than the number: a hide can be 1.8 mm and firm, or 1.8 mm and floppy, and only one of those makes a good notebook cover.

By The Leather Bench · Published 2026-09-15

Hide Weight: What Ounces Mean and When They Stop Working

Hole array drawn from the spacing in the spec table; dimensions in millimetres.

Reference table Ounce to millimetre, and what each weight is for

Ounce to millimetre, and what each weight is for
Weight (oz)Thickness (mm)FirmnessBest useAvoid for
2.5/31.0 – 1.2soft to mediumLinings, thin card slots, suedeAnything load-bearing
3/41.2 – 1.6mediumWallets, card holders, watch strapsBelts, bag gussets
4/51.6 – 2.0medium firmNotebook covers, aprons, small bagsHand-stitched tight curves
5/62.0 – 2.4firmBags, camera cases, dog collarsWallet interiors
6/72.4 – 2.8firmTool rolls, briefcase gussetsFolded linings
8/93.2 – 3.6very firmBelts, collars, sheaths, strapsAnything needing a 3 mm fold

Bench sequence in the order the bench asks for it

  1. The conversion, and where it lies

    One ounce equals 1/64 inch, or about 0.4 mm. So 4 oz is 1.6 mm, 6 oz is 2.4 mm and 8 oz is 3.2 mm. The ranges exist because a hide is not uniform: the butt is thicker and firmer than the belly, and a tannery sells a whole hide at an average weight. That is why a 5/6 oz shoulder and a 5/6 oz belly behave nothing alike.

    Buy shoulder or butt for anything structural and belly for linings and small flat goods. A 3/4 oz shoulder makes a wallet that holds its shape for a decade; a 3/4 oz belly makes the same wallet and it is soft within a year.

  2. Temper: the property nobody writes on the label

    Temper is how much the leather resists bending, and it is decided by the tannery's fatliquoring, not by thickness. Ask for firm temper when you need structure. On a notebook cover, a firm 1.6 mm panel holds an A5 refill upright; a soft 1.6 mm panel sags and the cover curls around the block.

    The test at the bench: hold a 100 mm strip of the hide out horizontally. A firm temper drops 20 to 30 mm at the tip. A soft one drops 60 mm or more. Do this before you cut, not after, because the whole order depends on it.

  3. What each weight refuses to do

    Every weight has a fold it cannot take. 8/9 oz will not fold back on itself without a skive down to 1.2 mm; force it and the grain cracks along the fold within weeks. 3/4 oz will not hold a bag gusset upright — it collapses at the first load, which is why gussets are cut from 4/5 oz or heavier.

    5/6 oz will not make a good wallet interior. It is 2.0 mm at the thinnest, and six card slots of it come to 12 mm of leather in a pocket. This is the single most common weight error on the bench: too heavy for interiors, too light for structure.

  4. Buying: one big panel beats four small ones

    A 0.3 m² panel of good 4/5 oz shoulder costs more per square decimetre than four 0.08 m² offcuts, but the offcuts have four different tempers and four different dye lots. On a project with five panels that match, that difference is visible.

    Buy the whole panel for anything over three pieces, cut the largest pieces first and work down. Store the rest flat under a board with a weight on it, never rolled — rolled leather takes a set within a month and a rolled hide cut later will not lay flat on the bench.

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