Waste in the kitchen means you pay more for your ingredients than you think. A kilo of onions costs €2, but after peeling you only have 900 grams left - d...
Waste in the kitchen means you pay more for your ingredients than you think. A kilo of onions costs €2, but after peeling you only have 900 grams left - so you're actually paying €2.22 per kilo of usable onion. In this article you'll learn step-by-step how to calculate your true food cost including waste and trim loss.
Why waste increases your food cost
Many business owners calculate based on the purchase price per kilo. But waste means you get less usable product for the same money. This raises your true food cost per portion.
💡 Example:
You buy 5 kg salmon for €90 (€18/kg). After filleting you have 2.8 kg fillet left:
- Purchase price: €18/kg
- Waste: 44% (head, bones, skin)
- True fillet price: €18 ÷ 0.56 = €32.14/kg
You're paying almost 80% more than you think!
The difference between purchase price and true food cost
The formula is simple but crucial:
True food cost = Purchase price ÷ (Yield ÷ 100)
Where yield = 100% minus waste percentage
⚠️ Attention:
NEVER multiply by the waste percentage. You have less product, so it becomes more expensive. Always divide by the yield.
Typical waste per ingredient
These percentages give you an indication. Measure yourself for accurate figures:
- Fish (whole to fillet): 40-55% waste
- Beef (trimming): 15-25% waste
- Vegetables (peeling): 15-25% waste
- Shrimp (peeling): 35-50% waste
- Fruit (peeling, pits): 20-40% waste
- Onions (peeling): 8-12% waste
Impact on your food cost
Waste can significantly increase your food cost without you noticing:
💡 Example steak:
Menu price: €32 incl. VAT (€29.36 excl. VAT)
- Beef: €24/kg, 200g portion = €4.80
- Trimming 20%: true price €30/kg = €6.00
- Other ingredients: €3.50
Food cost: €9.50 ÷ €29.36 = 32.4% (instead of 28.2% without waste)
Tracking waste in practice
Measure your waste for a week on the most important ingredients:
- Weigh before processing
- Weigh after processing
- Calculate the percentage
- Update your food costs
With an app like KitchenNmbrs you can set waste percentages per ingredient. The app then automatically calculates the true food cost for your recipes.
How do you calculate food cost with waste? (step by step)
Measure your waste percentage
Weigh your ingredient before and after processing for a week. Calculate the average waste percentage: (purchase weight - usable weight) ÷ purchase weight × 100.
Calculate the yield
Yield = 100% minus waste percentage. At 25% waste your yield is 75%. This is the percentage of usable product you keep.
Calculate the true food cost
Divide your purchase price by the yield (as decimal). At €20/kg and 25% waste: €20 ÷ 0.75 = €26.67/kg true food cost.
Update your recipes
Use the true food cost in your recipe calculations. Check if your selling prices still work with the higher ingredient costs.
✨ Pro tip
Measure waste on your 5 most expensive ingredients first. This is often where the biggest impact on your food cost is hidden.
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
Should I include waste in my food cost?
Yes, absolutely. Waste increases your true ingredient costs. If you ignore this, your food cost will appear lower than it really is.
How often should I measure my waste percentages?
Measure with new suppliers and seasonal changes. For vegetables this can vary per season, for meat and fish it's usually more stable.
Can I sell or reuse waste?
Some things yes: bones for stock, vegetable scraps for compost. But don't count on this - calculate your food cost including waste first.
What if my chef cuts differently than I calculate?
Train your kitchen team in standard portion sizes. Use a scale and show them what 200 grams of steak looks like. Consistency is crucial.
How do I prevent too much waste?
Buy products that better match your recipes. Sometimes pre-cut is more expensive per kilo, but cheaper per portion due to less waste.
📚 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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