Here's something most chefs discover too late: that "affordable" whole fish isn't cheap once you factor in the bones, head, and skin. New ingredients hide their true cost until you process them. You'll need the exact yield percentage to avoid menu pricing disasters.
What is a yield percentage?
The yield percentage shows what percentage of your purchase weight remains usable after processing. Fish loses the head, bones and skin. Vegetables lose peels and stems. This waste is trim loss.
💡 Example:
You buy 2 kg whole cod for €18/kg:
- Purchase weight: 2 kg
- After filleting: 1.1 kg fillet
- Yield percentage: (1.1 / 2.0) × 100 = 55%
Every kilo you pay for gives you just 550 grams of usable meat.
Why this matters for your cost price
Without the correct yield percentage, you're calculating with fantasy numbers. You think fish costs €18/kg, but you're actually paying €32.73/kg for the fillet. This mistake costs the average restaurant EUR 200-400 per month in underpriced dishes.
Formula for actual per-kilo price:
Actual price = Purchase price ÷ (Yield percentage ÷ 100)
💡 Calculation example:
Cod €18/kg with 55% yield:
- Actual fillet price: €18 ÷ 0.55 = €32.73/kg
- For 200g portion: €32.73 × 0.2 = €6.55
If you calculate with €18/kg you think 200g costs €3.60. You're €2.95 too low!
The test method: measure before you buy
For new ingredients, run a small test first. Buy a tiny quantity and measure the loss. This prevents expensive surprises with bulk purchases.
- Buy 1-2 pieces or 1 kg of the new product
- Weigh before and after processing
- Calculate the yield percentage
- Adjust your recipe costs
⚠️ Note:
Yield percentages vary by supplier and season. Summer zucchini has less waste than winter zucchini. So measure regularly.
Common yield percentages as starting points
If you can't test immediately, use these reference values. But adjust them later with your own measurements:
- Fish (whole to fillet): 45-60%
- Beef (whole to portions): 75-85%
- Vegetables (with skin): 80-90%
- Shrimp (unpeeled): 50-65%
- Chicken (whole to fillet): 65-75%
💡 Practical example:
You want to make a new fish dish with sea bream. You've never processed whole sea bream before:
- Start with 50% yield as an estimate
- Buy 1 fish of 400g for €8/kg
- After filleting: 180g fillet (45% yield)
- Actual fillet price: €8 ÷ 0.45 = €17.78/kg
Now you know the real cost price for your recipe.
Record digitally for consistency
Document your measured yield percentages in a system. Otherwise you'll forget them and repeat the same costly errors. Tools like KitchenNmbrs let you set yield percentages per ingredient, so your cost price calculates automatically and accurately.
This prevents you from guessing next month what cod actually costs after processing.
How do you measure the yield percentage? (step by step)
Weigh the raw product
Weigh the ingredient as you purchase it. With fish: the whole fish. With vegetables: including the skin. Note this weight as your starting point.
Process as in your recipe
Prepare the ingredient the way you use it in your dish. Fillet the fish, peel the vegetables, remove the fat. Do this exactly the way your chef always does it.
Weigh the usable end product
Weigh only what you actually use in your dish. Not the peels, bones or waste. This is your net weight.
Calculate the yield percentage
Divide the net weight by the gross weight and multiply by 100. Formula: (Net weight ÷ Gross weight) × 100 = Yield%
Adjust your cost price
Calculate your actual per-kilo price: Purchase price ÷ (Yield% ÷ 100). Update your recipe with this correct cost price per kilo.
✨ Pro tip
Test new ingredients during prep time 2-3 days before adding them to your menu. This gives you time to adjust recipes and pricing if the yield is lower than expected.
Calculate this yourself?
In the KitchenNmbrs app you can do this in just a few clicks. 7 days free, no credit card.
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Frequently asked questions
Do I need to do this for every new ingredient?
Yes, especially for expensive ingredients or if you're unsure about the waste percentage. With cheap herbs you can estimate, but with fish or meat a wrong estimate can cost you serious money.
How often should I remeasure the yield percentage?
For seasonal products every 3-4 months. For stable products like meat or fish 1-2 times per year. If you switch suppliers, always measure again.
What if my chef cuts differently than during the test?
Train your team to cut consistently. A chef who fillets more carefully gets better yield. Make agreements about how ingredients are processed and check this regularly.
Can I estimate the yield percentage without measuring?
For known products you can start with common percentages. But for expensive ingredients or new suppliers, measuring beats guessing every time.
How do I handle seasonal differences in yield?
Remeasure yield percentages when you notice more or less waste. Summer vegetables often have less waste than winter ones.
What's the biggest yield mistake restaurants make?
Using the purchase price instead of the actual usable price in recipes. A €20/kg ingredient with 60% yield actually costs €33.33/kg for menu costing.
Should I factor in cooking loss too?
Absolutely. Meat loses 20-30% weight during cooking, vegetables lose water content. Measure both prep loss and cooking loss for accurate portion costs.
📚 Sources consulted
- EU Verordening 852/2004 — Levensmiddelenhygiëne (2004) — Official source
- EU Verordening 853/2004 — Hygiënevoorschriften voor levensmiddelen van dierlijke oorsprong (2004) — Official source
- EU Verordening 1169/2011 — Voedselinformatie aan consumenten (2011) — Official source
- NVWA — Hygiënecode voor de horeca (2024) — Official source
- NVWA — Allergenen in voedsel (2024) — Official source
- Codex Alimentarius — International Food Standards (2024) — Official source
- FSA — Safer food, better business (HACCP) (2024) — Official source
- BVL — Lebensmittelhygiene (HACCP) (2024) — Official source
- Warenwetbesluit Bereiding en behandeling van levensmiddelen (2024) — Official source
- WHO — Foodborne diseases estimates (2024) — Official source
Food Standards Agency (FSA) — https://www.food.gov.uk
The HACCP standards shown in this application are for informational purposes only. KitchenNmbrs does not guarantee that displayed values are current or complete. Always consult the FSA or your local authority for the latest regulations.
Written by
Jeffrey Smit
Founder & CEO of KitchenNmbrs
Jeffrey Smit built KitchenNmbrs from 8 years of hands-on experience as kitchen manager at 1NUL8 Group in Rotterdam. His mission: give every restaurant owner control over food cost.
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