I've seen too many restaurants get burned by minimum purchase contracts that looked like great deals on paper. Sure, you get attractive discounts, but if you buy more than your actual demand, those savings quickly turn into losses through waste. Here's how to calculate your real margin and figure out if such contracts actually boost your profits.
What is a minimum purchase contract?
With a minimum purchase contract, you commit to purchasing a minimum quantity from a supplier within a certain period (usually per month or quarter). In return, you get a lower purchase price. The risk: if you sell less than expected, you're left with too much inventory.
Calculate your real costs
Your real costs consist of more than just the purchase price:
- Purchase price per unit (the contract price)
- Waste costs (what you throw away due to overstock)
- Storage costs (extra refrigeration space, energy)
- Capital costs (money tied up in inventory)
💡 Example:
Your supplier offers salmon at €16/kg with a minimum of 50kg per month (normally €20/kg). You sell an average of 40kg per month.
- Contract purchase price: €16/kg × 50kg = €800
- Actual usage: 40kg (€640 in sales)
- Surplus: 10kg (likely lost)
- Waste: 10kg × €16 = €160
Real price: €800 / 40kg = €20/kg
You end up paying the same as the normal price!
Formula for real cost price
The formula to calculate your real cost price:
Real cost price = (Total purchase costs + Waste costs + Storage costs) / Actual usage
⚠️ Note:
Always calculate with your actual consumption, not the minimum purchase quantity. Otherwise you'll get a distorted picture of your costs.
Determining contract profitability
A minimum purchase contract only makes sense if:
- You actually sell at least 80-90% of the minimum purchase quantity
- The contract price + waste costs are lower than the normal purchase price
- You have sufficient cash flow to cover the higher inventory value
- Your product has a long enough shelf life to absorb fluctuations
💡 Break-even calculation:
Contract: €16/kg, minimum 50kg. Normal price: €20/kg.
Break-even point: You need to sell at least 40kg to break even.
- 40kg × €20 (normal price) = €800
- 50kg × €16 (contract price) = €800
Sell less than 40kg? Then you lose money on the contract.
Factor in risk factors
Based on real restaurant P&L data, these risks consistently impact contract profitability. You should weigh them carefully:
- Seasonal variation: Do you sell less fish in winter than in summer?
- Shelf life: Can you freeze surplus without quality loss?
- Alternative use: Can you process surplus in other dishes?
- Cash flow impact: Do you have enough working capital for higher inventory?
Impact on your food cost
A minimum purchase contract affects your food cost calculation. Always calculate with your real cost price (including waste), not the contract price.
💡 Food cost impact:
Salmon dish sells for €32.00 (€29.36 excl. VAT), uses 200g salmon:
- With contract price: €16/kg → €3.20 per portion → 10.9% food cost
- With real price: €20/kg → €4.00 per portion → 13.6% food cost
The difference of 2.7 percentage points can significantly impact your margin.
Consider alternatives
Before signing a minimum purchase contract, look at these alternatives:
- Joint purchasing: Share minimum purchase with other restaurants
- Flexible contracts: Ask for discounts at higher volumes without minimum obligation
- Seasonal contracts: Only during busy periods
- Multiple suppliers: Spread your risk
A tool like KitchenNmbrs helps you track the real cost price of your ingredients, including waste and contract obligations. This way you immediately see whether such a contract increases or decreases your profit.
How do you calculate the margin on a minimum purchase contract?
Calculate your actual consumption per period
Look at your sales data from the last 3-6 months. Add up how much you sell on average per month of the product. Also factor in seasonal variations - do you sell 30% less in winter than in summer?
Calculate total costs including waste
Add to the contract price: waste costs (surplus × purchase price), extra storage costs and capital costs. Divide this by your actual consumption to get your real cost price per unit.
Compare with current purchase price and calculate impact
Compare your real cost price with your current purchase price. Calculate the difference per unit and multiply by your monthly consumption. This shows you whether the contract saves you money monthly or costs you money.
✨ Pro tip
Track your actual usage for 90 days before signing any minimum purchase contract - this gives you solid data on seasonal variations and realistic consumption patterns. Most restaurants overestimate their usage by 15-20%.
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
What if I don't meet the minimum purchase quantity?
Most suppliers will then charge the normal purchase price for the quantity actually purchased. Sometimes there's also a penalty for not meeting the minimum. Always check this in your contract.
Can I cancel a minimum purchase contract early?
That depends on your contract. Many contracts have a notice period of 1-3 months. Early termination may result in a penalty. Read the fine print carefully.
How do I prevent waste with overstock?
Try to process surplus in other dishes, offer special promotions, or ask your supplier for flexibility in delivery times. Some products can also be frozen without quality loss.
Should I include waste costs in my food cost?
Yes, absolutely. Your food cost should be based on your actual costs, including waste. Otherwise you'll get too rosy a picture of your profitability per dish.
📚 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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