Yield and waste in recipe costing: why your dish costs more than you think
Benn Asaraf ·
Every chef has done it. You cost the salmon at the invoice price per kilo. Then you pin-bone it, skin it and square it off. A good chunk of that kilo goes in the staff tray or the bin. Your sheet never saw it.
That gap is yield. It is why so many dish costs are wrong by 15% or more, and why GP on paper beats GP in the bank.
Cost what you buy, not what you plate
The invoice tells you what a kilo of fish costs. It does not tell you what a kilo of usable fish costs. Those are different numbers.
The rule is short:
Usable cost per kg = price per kg ÷ yield
Yield is the share you can actually serve, written as a decimal. If 1 kg of salmon side gives you 850 g of portions, the yield is 0.85.
At £18.00 a kilo, that salmon really costs £18.00 ÷ 0.85 = £21.18 per usable kilo. A 160 g portion costs £3.39, not the £2.88 your sheet says.
One dish, costed twice
Here is a simple main. Salmon, new potatoes, samphire, a beurre blanc. Same portions, same supplier prices. The only change is yield.
| Ingredient | Price | Yield | Portion | Cost at invoice price | Cost with yield |
|---|---|---|---|---|---|
| Salmon side | £18.00/kg | 85% | 160 g | £2.88 | £3.39 |
| New potatoes | £1.60/kg | 90% | 200 g | £0.32 | £0.36 |
| Samphire | £14.00/kg | 85% | 40 g | £0.56 | £0.66 |
| Butter | £7.00/kg | 100% | 30 g | £0.21 | £0.21 |
| Shallot | £2.40/kg | 80% | 15 g | £0.04 | £0.05 |
| Plate cost | £4.01 | £4.66 |
That is 65p a plate, or 16% more than the sheet says. Nothing fancy happened. You just trimmed the fish and picked the samphire.
Now put it on the menu at £24.00. Take the 20% VAT off first and you keep £20.00. (If that step is new to you, read GP and VAT in the UK.)
- At invoice prices: £4.01 ÷ £20.00 = 20.0% food cost, so 80.0% GP.
- With yield: £4.66 ÷ £20.00 = 23.3% food cost, so 76.7% GP.
Still a good dish. But sell 400 a month and that is £260 you thought you had and did not.
Three kinds of loss
Not all loss is the same. Keep them apart, or you will count one twice and miss another.
1. Trim loss. What comes off before cooking. Skin, bones, peel, root ends, outer leaves, stalks. You measure it raw.
2. Cooking loss. What goes when heat hits it. Water, fat, shrinkage. A joint of beef can lose a quarter of its weight in the oven. If your portion is weighed cooked, you need this number.
3. Waste. What you bought but never sold. Prep that went past its date. A tray dropped on the pass. A 180 g portion when the spec says 160 g. This one does not live in the recipe. It lives in your stock count.
Yield covers the first two. Waste is a kitchen habit, and you fix it with portion control and ordering, not with maths.
How to run a yield test
You need scales, a pen and ten minutes. Do it once per ingredient, then again when the supplier or the cut changes.
- Weigh the product as it arrives. Write it down.
- Prep it exactly the way your team does on a normal day. Not your best day.
- Weigh what you will actually use. Write it down.
- If the portion is weighed cooked, cook a batch and weigh it again.
- Divide usable weight by bought weight. That is your yield.
Do it with the person who preps it every day. Their yield is the one you pay for.
If you use the trim, say so. Salmon belly in a staff curry or a crudo is not waste. You can credit it back. Just be honest about how often it really gets used.
Rough yields to sanity-check your own
These are typical ranges, not your numbers. Test your own. They vary with the supplier, the season and the knife.
- Whole round fish to skinless fillet: 40 to 50%
- Trimmed salmon side to portions: 80 to 90%
- Onions and shallots, peeled: 80 to 90%
- Leeks, trimmed and washed: 50 to 65%
- Soft herbs, picked: 50 to 70%
- Roast beef joint, cooking loss: 20 to 30% (so 70 to 80% yield)
- Butter, oil, sugar, flour: close to 100%
If your sheet says 100% for anything with skin, bones or a root, it is wrong.
Where yield hides in sub-recipes
Stocks, sauces and bases are the other trap. You put 5 kg of bones and veg in a pot and get 2 litres out. If you cost the stock by what went in per litre of water, you are miles off.
Cost a sub-recipe the same way. Add up everything that went in. Weigh or measure what came out. Divide. Then use that cost per litre or per kilo in the dish.
Same with batches. Your 3 kg of braised short rib started as 4.5 kg raw. The cost of a cooked kilo is the cost of the raw batch divided by 3, not by 4.5.
Keep it current
A yield test is cheap. Re-costing every dish by hand when the fish price moves is not. That is where a spreadsheet starts to creak. (Spreadsheet or software goes into when it is worth switching.)
In Mise n' Price you set the yield once per ingredient, and batches carry their own finished weight. Scan the next invoice and the usable cost of every dish updates. If a yield looks off, like 20% on carrots, it asks you to check the weight before you trust it.
If you have not costed a dish from scratch before, start with how to cost a dish. Then come back and add yield. It is the step most sheets skip.
The short version
- Divide the invoice price by the yield before you cost anything.
- Test yield with your team's knife, not yours.
- Trim and cooking loss go in the recipe. Waste goes in the stock count.
- Cost stocks and batches by what comes out, not what goes in.
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Check your real GP now. Put your plate cost with yield into the free GP calculator. It takes the VAT off for you.
Want yield to update itself? Mise n' Price is in closed beta, free until 13 December. Apply for the beta.