Nearly 70% of restaurants miscalculate their actual food costs because they estimate unit prices instead of converting supplier packaging prices accurately. Your supplier quotes €18.50 for a carton of mushrooms, but you need to know the exact cost per kilo for your dishes. One small conversion error can cost you hundreds of euros monthly in lost profits.
Why this is crucial for your profitability
Your supplier says: "Carton of mushrooms costs €18.50." But how much does one kilo of mushrooms cost then? And what does that mean for the cost price of your risotto? Without this conversion, you don't know if your dish is profitable.
⚠️ Watch out:
Many entrepreneurs estimate the price per unit, which means they unknowingly earn too little on their dishes. A difference of €0.50 per kilo can mean hundreds of euros per month.
The basic conversion formula
The formula is simple, but you need to know exactly what's in the packaging:
Price per unit = Total packaging price ÷ Number of units in packaging
Sounds logical, but the devil is in the details. How much is really in that carton? And what if there are different sizes?
💡 Example: Mushroom carton
Your supplier charges €18.50 for a carton of mushrooms.
- Carton contains: 10 containers of 250 grams
- Total weight: 2.5 kg
- Price per kilo: €18.50 ÷ 2.5 = €7.40/kg
For your cost calculation, you use €7.40 per kilo of mushrooms.
Converting different packaging types
Every supplier works differently. Here are the most common situations you'll encounter:
Cartons with fixed contents
This is the easiest scenario. The invoice usually states: "Carton tomatoes 6kg" for €12.00. Then you pay €12.00 ÷ 6 = €2.00 per kilo.
Pallets and large units
With larger purchases, you often get a pallet price. For example: pallet of potatoes for €180, contains 40 bags of 25kg each.
💡 Example: Pallet calculation
Pallet of potatoes costs €180 and contains 40 bags of 25kg.
- Total weight: 40 × 25kg = 1,000kg
- Price per kilo: €180 ÷ 1,000kg = €0.18/kg
Much cheaper than small bags, but you need to be able to store and use 1,000kg before it spoils.
Units instead of weight
Some products you buy per unit: eggplants, peppers, zucchini. Then you need to know how many units are in a crate.
- Crate of eggplants: €15 for 24 units = €0.63 per eggplant
- Crate of peppers: €18 for 30 units = €0.60 per pepper
- Bunch of tomatoes: €2.20 per bunch, usually 6-8 tomatoes per bunch
Hidden costs you need to include
The supplier price isn't your real purchase price. One of the most common blind spots in kitchen management is forgetting these additional costs that can inflate your actual unit prices by 15-25%.
⚠️ Watch out:
Don't forget shipping costs, VAT, and minimum orders. A "cheap" supplier can end up being more expensive due to high shipping costs.
- Shipping costs: €25-50 per delivery, divide this over your order
- VAT: 9% on most food items (with some exceptions)
- Minimum orders: sometimes you have to buy more than you want
- Crate deposit: for crates and pallets
💡 Example: Calculate real purchase price
You order for €200 excl. VAT + €30 shipping + €18 VAT.
- Total paid: €248 incl. VAT
- Real purchase price: €230 excl. VAT (€200 + €30)
- This is what you use for cost calculation
Your products are therefore 15% more expensive than the catalog price suggests.
Track seasonal changes and price fluctuations
Suppliers adjust their prices regularly. Especially with fresh products, prices can change weekly. Keep track of this, otherwise your cost calculation won't be accurate anymore.
- Check prices with every delivery
- Update your cost prices when suppliers raise prices
- Watch for seasonal fluctuations (tomatoes much more expensive in winter)
- Compare regularly with other suppliers
Keeping track digitally saves time and prevents errors
Many entrepreneurs do this manually in Excel, but that's time-consuming and error-prone. With tools like KitchenNmbrs, you record supplier prices and the price per unit calculates automatically. Price changes? You'll immediately see the impact on your dishes' profitability.
How do you calculate the unit purchase price? (step by step)
Gather all packaging information
Check your invoice or ask your supplier: what exactly is in the carton, crate, or pallet? Not just the total weight, but also how many units or which packages. For example: carton contains 12 bags of 500 grams = 6 kg total.
Calculate the basic price per unit
Divide the total price by the number of units. For weight: total price ÷ total kilograms. For units: total price ÷ number of units. Use the price excl. VAT for your cost calculation.
Add shipping and extra costs
Divide shipping costs over your entire order. If you pay €30 shipping on €300 worth of products, then your products are 10% more expensive. Use this real purchase price for your food cost calculation.
✨ Pro tip
Create a quick reference sheet with your top 15 supplier items and their exact carton contents - tape it inside your walk-in cooler door. You'll save 10 minutes per delivery doing instant unit price calculations without hunting for packaging details.
Calculate this yourself?
In the KitchenNmbrs app you can do this in just a few clicks. 7 days free, no credit card.
Was this article helpful?
Frequently asked questions
Should I include VAT in my unit purchase price?
No, always calculate with prices excl. VAT. Your selling price is also excl. VAT for food cost calculation. VAT is a pass-through item that you pass on to your guests.
What if my supplier has different packaging sizes?
Calculate the price per unit separately for each packaging size. Often the larger package is cheaper per kilo, but you need to be able to store and use it before it spoils.
How often should I update my purchase prices?
Check with every delivery whether the prices are still correct. Suppliers raise prices regularly, especially for fresh products. Update your cost prices immediately, otherwise you'll unknowingly earn less.
Should I include shipping costs for small orders?
Yes, especially for small orders, shipping costs can make your products 10-20% more expensive. Divide the shipping costs over your entire order to get the real purchase price.
What if I order from multiple suppliers?
Keep track per supplier of what you really pay per product including shipping. Compare regularly which supplier is cheapest for which product, taking into account quality and reliability.
How do I handle partial cartons or broken packaging?
Calculate based on what you actually receive, not what the carton should contain. If a 10kg carton arrives with only 9.2kg due to damage, use 9.2kg in your calculation. Always weigh irregular shipments to maintain accurate unit 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.
Optimize your purchasing with data
Know exactly which supplier is most cost-effective and how price changes affect your margins. KitchenNmbrs links purchasing directly to recipe costs. Try it free for 14 days.
Start free trial →