Accurate cost pricing requires knowing your true average spend per unit across all suppliers. If you're sourcing the same ingredient from multiple vendors at varying prices, using just one supplier's rate skews your calculations. Your actual food costs and profit margins depend on this weighted average.
Why the average purchase price matters
Buying steak from supplier A at €28/kg and supplier B at €32/kg means you can't just pick one price for your calculations. Your real cost sits somewhere between those figures, weighted by purchase volumes from each source.
💡 Example:
You buy steak from 2 suppliers:
- Supplier A: 40 kg for €28/kg = €1,120
- Supplier B: 20 kg for €32/kg = €640
Total: 60 kg for €1,760
Average purchase price: €1,760 ÷ 60 kg = €29.33/kg
The weighted average formula
A proper average purchase price uses weighted averaging. This accounts for how much you actually buy from each supplier, not just their individual rates.
Formula:
Average purchase price = (Total costs all suppliers) ÷ (Total quantity all suppliers)
💡 Practical example:
You buy salmon from 3 suppliers in January:
- Supplier A: 15 kg × €22/kg = €330
- Supplier B: 25 kg × €24/kg = €600
- Supplier C: 10 kg × €20/kg = €200
Total: 50 kg for €1,130
Average: €1,130 ÷ 50 kg = €22.60/kg
⚠️ Watch out:
NEVER calculate the average of the prices (€22 + €24 + €20) ÷ 3 = €22. This ignores purchase volumes and gives you incorrect costs.
Recalculation timing
Your average purchase price shifts whenever:
- A supplier adjusts their pricing
- You change your buying ratios between suppliers
- You onboard new suppliers or drop existing ones
- Quality variations influence your sourcing decisions
Most restaurants review these figures monthly to maintain accurate costing. From tracking this across dozens of restaurants, those updating weekly during volatile periods see tighter margin control.
Food cost impact
Small per-unit differences compound quickly across your volume:
💡 Impact calculation:
250 gram steak, sold for €32 (excl. VAT €29.36):
- At €28/kg: 0.25 kg × €28 = €7 → food cost 23.8%
- At €30/kg: 0.25 kg × €30 = €7.50 → food cost 25.5%
Difference: 1.7 percentage points less margin per steak
Manual tracking vs. digital systems
Excel tracking means manually processing purchase invoices monthly and recalculating everything. Time-consuming and error-prone.
Digital systems can record multiple suppliers per ingredient with their current pricing. The platform automatically calculates weighted averages based on actual purchase data, keeping your cost prices current without manual work.
How do you calculate the average purchase price? (step by step)
Gather all purchase data
Note from each supplier: how many kg/units you bought and what the price per unit was. Check your invoices from the past month.
Calculate total costs per supplier
For each supplier, multiply: quantity × price per unit. Add all amounts together for the total amount you spent on this product.
Divide by total quantity
Divide the total amount by the total quantity you purchased. This is your weighted average purchase price that you use in your cost price calculation.
✨ Pro tip
Track your top 8 ingredients by monthly spend over the next 6 weeks. These typically represent 75% of your food costs, so getting their averages right fixes most pricing issues.
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 every ingredient?
Only for ingredients you buy from multiple suppliers. Products sourced from a single vendor just use that supplier's price.
How often do I need to recalculate this?
At least monthly, or immediately after supplier price changes. During periods of high price volatility, weekly updates give you better control.
What if quality differs per supplier?
Create separate recipe entries or track those ingredients individually. Don't average different quality grades into one price point.
What if I buy different package sizes?
Convert everything to the same unit (per kg, per liter) before calculating. Watch for price variations due to packaging differences.
📚 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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