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.
How much to buy
As-purchased (AP) weight = the edible weight you need (EP) ÷ the yield. At 90%:
| Usable weight needed | Buy (as purchased) |
|---|---|
| 1 kg | 1.11 kg |
| 5 kg | 5.56 kg |
| 10 kg | 11.11 kg |
Cost works the same way: usable cost per kilo = the price per kilo you pay ÷ 0.90. At £1.00 a kilo as purchased, usable onions cost £1.11 a kilo.
Use 90% in the yield calculator →
Where the numbers come from
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. These are averages from US samples of brown onions, weighed before and after each stage of prep. Varieties, sizes, UK grading and your own knife work all move the number, which is why every row shows the range as well as the average.
Use these figures to plan and to sense-check. To cost a dish properly, weigh your own: weigh a case as it arrives, prep it the way you do in service, weigh what is usable, and put both weights into the yield calculator.
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