Courgettes yield: how much is usable after prep (AP to EP %)
Courgettes: about 93% usable going whole to trimmed (ends off), with a published range of 86–98%. That is a cost factor of 1.08: for every kilo you need ready to use, buy 1.08 kg as purchased.
Yield by preparation stage
| Stage | Average | Range | What is lost | USDA item |
|---|---|---|---|---|
| Whole courgette → flesh and skin (ends off) | 93% | 86–98% | Ends | 2446 |
| Whole courgette → peeled flesh | 82% | 74–90% | Ends and skin | 2448 |
| Trimmed → sliced | 98% | 98–99% | Slicing loss | 2449 |
| Ready to cook → steamed (all summer squash) | 88% | 69–99% | Net losses | 2451 |
| Ready to cook → boiled (all summer squash) | 81% | 66–94% | Net losses | 2452 |
| Frozen sliced courgettes → boiled | 73% | 65–82% | Net losses | 2456 |
Yields multiply: 93% × 98% ≈ 91% for whole → sliced. You never add the losses together.
Courgettes lose very little to the knife and more in the pan, because they are mostly water. Cost a courgette side on the cooked weight.
How much to buy
As-purchased (AP) weight = the edible weight you need (EP) ÷ the yield. At 93%:
| Usable weight needed | Buy (as purchased) |
|---|---|
| 1 kg | 1.08 kg |
| 5 kg | 5.38 kg |
| 10 kg | 10.75 kg |
Cost works the same way: usable cost per kilo = the price per kilo you pay ÷ 0.93. At £1.00 a kilo as purchased, usable courgettes cost £1.08 a kilo.
Use 93% 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 2446, 2448, 2449, 2451, 2452, 2456. These are averages from US samples of whole courgettes (zucchini); the cooked rows cover all summer squash, 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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