Onions yield: how much is usable after prep (AP to EP %)
Onions: about 90% usable going whole to peeled, with a published range of 50–99%. That is a cost factor of 1.11: for every kilo you need ready to use, buy 1.11 kg as purchased.
Yield by preparation stage
| Stage | Average | Range | What is lost | USDA item |
|---|---|---|---|---|
| Whole → peeled (top, tail and skin off) | 90% | 50–99% | Skin, ends, sprouts and defects | 1568 |
| Peeled → chopped | 92% | 89–96% | Cutting loss | 1571 |
| Peeled → cooked (baked, boiled or steamed) | 85% | 67–103% | Water lost in cooking | 1572 |
Yields multiply: 90% × 92% ≈ 83% for whole → chopped. You never add the losses together.
Sprouted onions drop to about 82% peeled (item 1570), so the age of the sack matters as much as the knife work.
Prep notes
Top and tail without taking a slice off the root, then split and peel: the root end holds the layers together while you dice, and every extra slice off either end is a few per cent of the sack. Peel a whole tray before service rather than one at a time and the loss is the same but the time halves.
What the yield does to the cost
Brown cooking onions, 10 kg sack at £7.49 (JJ Foodservice, 10 Oct 2026) is £0.75 a kilo as purchased. At 83% usable that is £0.90 per usable kilo.
Worked example: a 5 kg batch of chopped onion for the week's sauces needs 6,024 g as purchased, costing £4.51. Costed on the bought weight it would read £3.75, so the costing would be 17% light.
| Usable onions needed | Buy (as purchased) at 90% |
|---|---|
| 1 kg | 1.11 kg |
| 5 kg | 5.56 kg |
| 10 kg | 11.11 kg |
Use 90% in the yield calculator →
Typical uses
The base of most savoury cooking: mirepoix and soffritto, gravy, curry bases, bolognese and chilli, French onion soup, and sliced for burgers and onion rings.
Storage and the trim
Keep sacks cool, dry and dark, off the floor and away from potatoes (which make them sprout). A sprouted onion drops to about 82% usable. Peeled onions keep two or three days covered in the fridge; chopped, use the same day or the next. Skins and ends go in the stock bag; the papery skins also colour a brown stock.
Yield source: USDA Agriculture Handbook No. 102, Food Yields Summarized by Different Stages of Preparation (Matthews and Garrison, USDA Agricultural Research Service, 1975), Table 1, items 1568, 1571, 1572 (US samples of brown onions). Prices as stated, read on 10 Oct 2026. Your own case is the real number: weigh it in the yield calculator.
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