Connecting purchase prices to your dishes forms the backbone of accurate cost calculation. Many restaurants estimate their food cost, which causes them to lose money without knowing it. Here's how to set up a system where you always know what each dish really costs.
Why linking purchase prices is crucial
Without linked purchase prices, you're flying blind. Your chef uses 200 grams of beef, but you're calculating with last month's price. Meanwhile, meat has become 15% more expensive. Every steak you sell now costs you too much.
⚠️ Note:
Suppliers regularly raise their prices. If you don't track this in your cost calculation, you think you're making a profit while actually losing money.
The foundation: one central ingredient list
Start by gathering all the ingredients you use in one place. Not per dish, but every ingredient from your entire kitchen. Think of:
- Main ingredients (meat, fish, vegetables)
- Basic products (oil, butter, salt, pepper)
- Sauces and dressings
- Garnish and decoration
Many kitchens forget the small things. That 5 grams of butter per plate seems like nothing, but at 100 covers per day that's €1,872 per year on butter alone.
💡 Example:
Pasta carbonara - forgotten ingredients:
- Olive oil for cooking: €0.15
- Butter on plate: €0.18
- Parsley garnish: €0.08
- Salt, pepper, herbs: €0.05
Extra costs per plate: €0.46
Keep purchase prices current
Your purchase prices change constantly. Every week you get new price lists from suppliers. The key is checking this weekly, not monthly.
Focus on your top 10 ingredients - they determine 80% of your total food cost. Check every week:
- Are there price changes from suppliers?
- Does the price still match your last invoice?
- Do you have an alternative supplier that's cheaper?
💡 Example:
Beef price update:
- Last month: €28.00/kg
- This week: €32.20/kg
- Difference: +15%
Per steak (250g): €1.05 extra costs. At 50 steaks per week = €2,730 per year impact.
Creating the link between ingredient and dish
Now comes the most important part: for each dish, document which ingredients are in it and how much. Not estimates, but exact weighing and measuring.
For each dish you note:
- Which ingredient (linked to your central list)
- How many grams/ml/pieces per portion
- Current purchase price per unit
- Cost per portion (automatically calculated)
⚠️ Note:
Calculate with net weight, not gross. If you buy 300g whole fish but get 180g fillet, calculate with the fillet price, not the whole fish price.
Set up automatic recalculation
The beauty of a good system: if you change the purchase price of one ingredient, all dishes with that ingredient are automatically recalculated. From analyzing actual purchasing data across different restaurant types, this automation prevents the costly lag time between price changes and menu adjustments that can eat into profits for weeks.
💡 Example:
Salmon price rises from €24/kg to €28/kg:
- Salmon salad: +€0.80 per portion
- Salmon terrine: +€1.20 per portion
- Grilled salmon: +€1.00 per portion
In one click you see the impact on all your salmon dishes.
Digital vs. Excel: why one system makes more sense
Excel can do it, but it costs you hours per week. And with every price change you have to manually adjust all formulas. Tools like KitchenNmbrs handle this automatically.
Benefits of one digital system:
- Central ingredient library
- Automatic recalculation when prices change
- Mobile: update prices from your phone
- No formula errors
- Cloud backup
Many restaurant owners start with Excel and switch to an app once they realize how much time it saves.
How do you link purchase prices to dishes? (step by step)
Create a central ingredient list
Gather all the ingredients you use in one overview. Note for each ingredient the supplier, packaging unit, and current purchase price. Don't forget small ingredients like oil, herbs, and garnish.
Weigh and measure all portions exactly
Go through each dish and weigh exactly how much of each ingredient you use per portion. Don't estimate, actually weigh it. Note this in grams, ml, or pieces per portion.
Calculate cost per portion automatically
Link the quantity per portion to the purchase price from your ingredient list. Let the system automatically calculate what each portion costs. Update your purchase prices weekly so the calculation stays current.
✨ Pro tip
Update your top 3 protein costs every Tuesday morning - these single ingredients typically represent 40-50% of your total food cost and fluctuate most dramatically. Miss a price jump here and you'll feel it in your margins within 48 hours.
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 weigh all ingredients or can I estimate?
Weighing is much more accurate. A teaspoon of salt can be 3-8 grams, depending on who does it. At 100 portions per day that makes a significant difference.
How often should I update my purchase prices?
At least weekly for your top 10 ingredients. These determine 80% of your total food cost. You can check other ingredients monthly.
What if my supplier raises the price?
Update the purchase price in your system immediately. Check which dishes become more expensive and whether you need to adjust your menu price to maintain your margin.
Should I also include herbs and oil in the cost price?
Absolutely. That 5 grams of butter per plate seems small, but at 100 covers per day that's almost €2,000 per year on butter alone.
📚 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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