Nearly 40% of restaurant partnerships fail within the first year, often due to unclear cost-sharing agreements on shared ingredient purchases. Many chefs split invoices fifty-fifty without considering actual quantities or proportional shipping costs. This simple mistake can throw off your food cost calculations by 15-20% monthly.
Why shared purchasing is complex
Buying with another chef gets you better volume pricing, but invoices contain mixed products, quantities, and prices. Without tracking your exact share, food cost accuracy goes out the window.
⚠️ Heads up:
Never divide the total invoice by 2. You're probably taking different products and quantities home.
The correct calculation method
Your purchase price has three components: the product cost, proportional shipping, and any extra fees like minimum order charges.
💡 Example:
Joint fish supplier order:
- You: 5 kg salmon at €22/kg = €110
- Colleague: 8 kg tuna at €28/kg = €224
- Shipping costs: €15 total
Your shipping share: €15 × (€110 / €334) = €4.94
Your actual salmon price: (€110 + €4.94) / 5 kg = €22.99/kg
Dividing shipping and extra costs
Split shipping proportionally based on order value. Got 30% of the total order? You cover 30% of shipping. Much fairer than going halves, especially when order sizes differ significantly.
Administrative fees and minimum order surcharges follow the same rule. Always keep the original invoice and document who took what – it's the kind of thing you only learn after closing your first month at a loss.
💡 Calculation example:
Invoice totaling €500, shipping €20:
- Your products: €180
- Colleague products: €300
- Your shipping share: €20 × (€180/€480) = €7.50
Your total costs: €180 + €7.50 = €187.50
Administration for shared purchasing
Document each order: date, supplier, your products with quantities, total invoice value, and your share of additional costs. Snap photos of invoices and share them immediately.
For food cost tracking, enter the actual price per kilo including your proportional shipping and fees. This ensures accurate cost calculations.
⚠️ Heads up:
Set clear payment and division agreements upfront. Money disputes can destroy professional relationships quickly.
VAT and taxes with shared purchasing
VAT applies to the entire original invoice. If both parties are VAT-registered, no issues arise. But when one isn't registered for VAT, complications multiply.
For bookkeeping: retain the original invoice and create a detailed cost breakdown. Some accountants recommend internal invoices for cost pass-through transactions.
How do you calculate the purchase price with shared purchasing?
Determine your product costs
Add up all the products you're taking from the invoice. Multiply quantity × price per unit for each product. This gives you your total product value.
Calculate your share of extra costs
Divide shipping and other surcharges proportionally based on your order value. Formula: Extra costs × (your product value / total invoice value).
Calculate actual price per kilo
Add your product costs and share of extra costs together. Divide this by the total weight you're taking. This is your actual purchase price per kilo for your food cost calculation.
✨ Pro tip
Create a standard formula and stick to it: (your products + (shipping × your percentage)) ÷ total weight = true cost per kilo. Use this same calculation for every shared order over the next 90 days to build consistency.
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
Should I always include shipping in my purchase price?
Absolutely – shipping represents real costs that impact your margins. Excluding it makes your food costs appear artificially low, leading to pricing mistakes that hurt profitability.
What if my colleague orders significantly more than agreed?
Establish maximum order limits per person upfront. When someone exceeds limits, they absorb proportionally more shipping costs. Clear communication prevents disputes and maintains fairness.
How should I handle VAT when my colleague isn't VAT-registered?
This creates complexity since you can deduct VAT but they can't. Consult your accountant about proper administrative handling – some recommend internal invoicing for cost transfers. Don't guess on tax matters.
📚 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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