What share of a raw hide ends up as leather, and how do I turn per-tonne-of-hide figures into figures per kilogram of leather?

The European tanning reference document says about 20 to 25% of the weight of a salted raw bovine hide becomes leather, 12 to 15% for sheep or goat skins and about 65% for sole leather. Divide a per-tonne-of-hide figure by that yield to get a figure per tonne of leather.

The yields the document prints

• Bovine hides: about 20 to 25% of the raw (salted) hide weight is transformed into leather.
• Sheep or goat skins: 12 to 15%, on salted raw skins.
• Sole leather: approximately 65%.
• Its input and output chart for one tonne of raw hide shows about 500 kilograms (kg) of chemicals going in and 200 to 250 kg of leather coming out, which matches the bovine yield.

How to convert

1. Work out the figure per tonne of raw hide first, from a month of bills and hide weights.
2. Divide by the yield as a fraction: 0.20 to 0.25 for bovine. A lower yield means each tonne of leather carries more of the tannery's energy and water.
3. State the yield you used and where it came from. If you weigh your own finished leather, use your own yield; it beats the document's range.

What the yield cannot do

It is a weight yield, so it gives you a figure per kilogram of leather, not per square foot. Finished leather weight depends on moisture and thickness. For a figure per square foot, measure area after finishing and divide the month's total by it. The live page on carbon per square foot of leather covers the unit conversion.

Why the per-tonne figures matter for waste and chemicals too

The same chart lists, per tonne of raw hide, about 15 to 50 cubic metres of water, about 450 to 730 kg of solid waste and about 500 kg of sludge at 40% dry matter. They are all per tonne of raw hide, so the same division applies.

Example: 16.8 gigajoules (GJ) per tonne of raw hide

• Per tonne of leather at 25% yield: 16.8 / 0.25 = 67.2 GJ
• Per tonne of leather at 20% yield: 16.8 / 0.20 = 84.0 GJ
• Water of 15 to 50 cubic metres per tonne of raw hide: 15 / 0.25 = 60 and 50 / 0.20 = 250, so 60 to 250 cubic metres per tonne of leather
• GJ per tonne is the same number as megajoules per kilogram, so 67.2 to 84.0 megajoules per kilogram of leather

The 16.8 GJ is an example month. Yield is the document's printed range for salted bovine hides, not a measured figure for your tannery.

What Senseible does here

Senseible reads fuel invoices and electricity bills into records by billing period, so the energy side of the division is on file by month. Hide weights and finished leather weights come from your own production records.

• Carbon footprint per square foot of leather
• Tannery energy per tonne of raw hide
• Carbon per kilogram instead of per piece

Sources: European Commission, Integrated Pollution Prevention and Control (IPPC) Reference Document on Best Available Techniques for the Tanning of Hides and Skins, February 2003 edition (filed by the publisher as superseded)

Last reviewed 2026-11-06. Figures are from the February 2003 edition of the European tanning reference document, which the publisher files as superseded; its energy and effluent tables rest on European tanneries and on older studies. Check the current edition and your own records before you quote a number to a buyer.