While many restaurants split ingredient costs equally across dishes, this approach creates massive blind spots in your profitability analysis. A salmon tartare uses three times more fish per portion than salmon soup, yet most operators calculate them identically. This proportional method reveals which dishes actually drive profits.
Why this matters
Say you buy a whole salmon of 3 kg for €54. You use this salmon in five different dishes: salmon tartare, grilled salmon, salmon risotto, salmon burger and salmon soup. Without proper distribution, you can't identify which dish generates the most profit.
⚠️ Note:
Many entrepreneurs divide costs equally across all dishes. That's incorrect. A salmon tartare uses more salmon per portion than salmon soup.
The correct distribution method
You distribute costs based on actual usage per dish. Not equal division, but proportional to weight. This is a pattern we see repeatedly in restaurant financials - operators who switch from equal division to proportional costing often discover their "star" dishes are actually loss leaders.
💡 Example:
Whole salmon: 3 kg for €54 = €18/kg
After filleting: 1.8 kg fillet (40% trimming loss)
Actual fillet price: €54 / 1.8 kg = €30/kg
Use this €30/kg for all calculations.
Calculate cost per dish
For each dish, calculate costs separately based on the weight used:
- Salmon tartare: 120g salmon × €30/kg = €3.60
- Grilled salmon: 180g salmon × €30/kg = €5.40
- Salmon risotto: 80g salmon × €30/kg = €2.40
- Salmon burger: 100g salmon × €30/kg = €3.00
- Salmon soup: 40g salmon × €30/kg = €1.20
💡 Check:
Add up all quantities used:
120g + 180g + 80g + 100g + 40g = 520g per round
With 1.8 kg fillet you can make 3-4 rounds.
Include trimming loss
Don't forget trimming loss. With fish you'll always have loss from head, bones and skin. This loss must be included in your cost price.
💡 Trimming loss calculation:
- Whole salmon: 3 kg for €54
- After filleting: 1.8 kg usable
- Trimming loss: 40%
- Actual price: €54 / 1.8 kg = €30/kg
NOT: €18 × 0.60 = €10.80 (this is wrong!)
Add other ingredients
Don't forget the other ingredients per dish:
- Garnishes and vegetables
- Sauces and oils
- Herbs and spices
- Bread or side dishes
Add everything up for the total cost price per dish.
Calculate food cost
With the correct cost price per dish, you calculate the food cost:
Food cost % = (Total ingredient costs / Selling price excl. VAT) × 100
💡 Example salmon tartare:
- Salmon: €3.60
- Avocado: €0.80
- Bread: €0.60
- Other: €1.00
Total: €6.00
Selling price: €18.50 incl. VAT = €16.97 excl. VAT
Food cost: (€6.00 / €16.97) × 100 = 35.4%
Digital vs. manual tracking
You'll need these calculations for each dish separately. With many shared ingredients this quickly becomes complex. Tools like KitchenNmbrs automatically calculate the correct distribution and maintain all cost prices without requiring manual math.
How do you calculate cost distribution? (step by step)
Calculate the actual price per kilo after loss
Divide the total purchase price by the usable weight after processing. For fish: divide by the fillet weight, not the whole weight. For vegetables: divide by the weight after peeling.
Determine usage per dish
Measure how many grams of the ingredient go into each portion. Be precise - a 20 gram difference can mean €0.50 per portion. Note this for all dishes that use the ingredient.
Calculate costs per dish
Multiply the usage per portion by the actual price per kilo. Add up all other ingredients for the total cost price. Then calculate the food cost percentage per dish.
✨ Pro tip
Track your 4 most expensive shared ingredients for the next 2 weeks - weigh every portion going out. You'll discover portion inconsistencies that are costing you 8-12% in food costs you didn't know existed.
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 always include trimming loss in the cost price?
Yes, always. Trimming loss makes ingredients more expensive than the purchase price. With fish this can be 40-50%, with meat 15-25%. Always calculate with the actual price per kilo after processing.
How do I distribute costs if I use different qualities?
Then use different prices. The best salmon for tartare costs more than the scraps for soup. Calculate an average price per quality and distribute based on that specific grade.
What if I don't know exactly how much I use per dish?
Measure it for a week. Have your chef weigh each portion and note the average. This time investment pays off with better cost prices and you'll spot portion creep immediately.
How often should I update these calculations?
Every time your supplier changes prices. Check at least monthly whether your purchase prices are still correct. Suppliers often raise prices without you noticing.
📚 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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