Think of your ingredients like a shared resource - one purchase price, but different portions going to different dishes. Many restaurant owners mess this up by simply dividing the total cost by dish count, ignoring portion differences. You must calculate the exact grams per dish and their individual costs.
Why this matters
Say you buy 5 kg of beef for €90. You use this meat for steak (200g), stew (150g), and carpaccio (80g). The purchase price is €18/kg, but each portion costs differently:
- Steak: 200g × €18/kg = €3.60 per portion
- Stew: 150g × €18/kg = €2.70 per portion
- Carpaccio: 80g × €18/kg = €1.44 per portion
Without proper tracking, you can't identify which dish brings the most profit.
💡 Example:
You buy salmon for €24/kg and use it in 3 dishes:
- Salmon fillet: 180g = €4.32 per portion
- Salmon salad: 120g = €2.88 per portion
- Salmon tartare: 100g = €2.40 per portion
Same product, but different cost prices per dish.
The correct calculation formula
For each dish using the ingredient:
Cost price per portion = (Portion weight in grams / 1000) × Purchase price per kg
This formula works for any ingredient appearing in multiple dishes: meat, fish, vegetables, herbs, oils.
⚠️ Note:
Don't forget to factor in cutting loss. If you have 20% loss when filleting fish, your actual price per kilo goes up: €24/kg becomes €24/0.80 = €30/kg for the fillets.
How to organize this
Create a list of all ingredients used across multiple dishes. After managing kitchen operations for nearly a decade, I've learned that tracking these details prevents costly oversights. For each ingredient, document:
- Purchase price per kg (including any cutting loss)
- Which dishes contain it
- Portion size in grams for each dish
- Individual cost per portion per dish
💡 Practical example:
Mushrooms €8/kg, used in:
- Risotto: 80g = €0.64 per portion
- Omelet: 60g = €0.48 per portion
- Salad: 40g = €0.32 per portion
- Pasta: 70g = €0.56 per portion
This way you see exactly what each dish costs in mushrooms.
Digital vs. manual tracking
Many kitchens rely on Excel, but it gets messy fast. If your supplier raises prices, you'll manually update every dish. A food cost calculator like KitchenNmbrs automatically recalculates all dish costs once you update the purchase price.
The benefit: you instantly spot which dishes become unprofitable and need price adjustments.
How do you calculate the cost price per dish? (step by step)
Determine the actual purchase price per kg
Take the price you pay and factor in any cutting loss if applicable. With 20% loss: divide by 0.80. With whole fish that you fillet: calculate based on the fillet price, not the price of the whole fish.
Measure the exact portion size per dish
Weigh how many grams of this ingredient you use in each dish. Do this for a few portions and take the average. Be precise — 10 grams difference can matter a lot.
Calculate the cost price per portion per dish
Use the formula: (grams per portion / 1000) × price per kg. Do this for each dish where you use the ingredient. Update this calculation every time your supplier raises the price.
✨ Pro tip
Identify your 3 most expensive shared ingredients and track them precisely for the next 30 days. This covers roughly 70% of your multi-dish cost accuracy with minimal effort.
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 all ingredients?
Start with your most expensive ingredients used across multiple dishes: meat, fish, premium vegetables. These create the biggest cost impact. Salt and pepper can wait.
How often should I update the prices?
Review supplier prices monthly at minimum. Major increases over 10% require immediate recalculation to ensure your menu prices still work.
What if I have different suppliers for the same product?
Calculate using your primary supplier's price. Or create a weighted average if you split purchases - say 70% from supplier A, 30% from supplier B.
How do I handle seasonal products that vary greatly in price?
Use the annual average price, or adjust costs seasonally. Asparagus in May costs differently than March. Update your food cost calculations accordingly.
Can't I just estimate this?
Estimates create 20-30% errors. An ingredient costing €2 per portion could be off by €0.40-€0.60, costing hundreds in lost profit annually.
What about ingredients with very small portions like spices?
Focus on high-impact ingredients first. Spices used in tiny amounts won't dramatically affect your margins compared to proteins and main vegetables.
How do I track prep waste when calculating portions?
Measure your actual yield after prep work. If 1kg of whole fish yields 750g of fillets, calculate costs based on the 750g usable portion.
📚 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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