Most restaurants nail their regular service but struggle with running dinners. The unpredictable nature means waste can easily hit €2-5 per person through overproduction and spoilage. Here's how to calculate exactly what that waste costs you per guest.
Why calculate waste costs?
Running dinners make portion estimation tricky. Under-buy and you're sold out by 9 PM. Over-buy and you're watching profits disappear into the trash. Calculating per-person waste costs gives you concrete data to work with instead of guessing.
⚠️ Note:
Waste isn't just what you throw away. Overproduction that you later have to sell at a discount also counts.
The three types of waste at a running dinner
Waste hits you at different points throughout the evening:
- Overproduction: Too much prepared for the expected number of guests
- Spoilage: Products that go past their date during the event
- Leftovers: What guests leave on their plates
💡 Example:
Running dinner for 100 people, you prepped for 120:
- Ingredients for 120 people: €720
- Actual number of guests: 100
- Waste: 20 portions = €144
Waste costs per person: €144 ÷ 100 = €1.44
Formula for waste costs per person
The basic formula is straightforward:
Waste costs per person = Total waste costs ÷ Actual number of guests
But you'll need to calculate total waste costs first:
- Overproduction: (Prepared portions - Served portions) × Cost per portion
- Spoilage: Purchase value of spoiled products
- Leftovers: Estimated percentage of what guests leave × Total production costs
💡 Example calculation:
Running dinner 80 people:
- Overproduction: 15 portions × €6 = €90
- Spoilage: €25 in spoiled vegetables
- Leftovers: 10% of €480 production costs = €48
Total: €163 ÷ 80 people = €2.04 per person
Tracking during service
Accurate measurement requires real-time tracking during your running dinner. This is the kind of thing you only learn after closing your first month at a loss - you can't fix what you don't measure.
- How many portions you prepared per dish
- How many portions were actually served
- What was left over at the end of the evening
- What you had to throw away due to spoilage
Most caterers use a simple counting app or notepad during service. Some use tools like food cost calculators to register this per event and get automatic calculations.
💡 Practical example:
Restaurant with running dinner every Friday:
- Week 1: €2.80 waste per person
- Week 2: €1.90 per person (better estimate)
- Week 3: €1.20 per person (optimal planning)
Difference: €1.60 per person savings through better planning
Benchmarks and target values
Here's what you should aim for with waste costs at running dinners:
- Good: €1.00-€1.50 per person (5-8% of food cost)
- Average: €2.00-€3.00 per person (10-15% of food cost)
- Too high: Above €3.50 per person (>15% of food cost)
These are guidelines, not rules. At very exclusive dinners with expensive ingredients, absolute amounts might be higher, but the percentage should stay comparable.
Reducing waste
Armed with these figures, you can make targeted improvements:
- Better estimation: Use historical data from similar events
- Flexible planning: Prepare 90%, keep 10% reserve ingredients
- Alternative destination: Plan what to do with leftovers (staff meal, next day)
- Portion monitoring: Train staff to serve consistent portions
How do you calculate waste costs per person? (step by step)
Register all waste
Track during the running dinner: how many portions prepared, how many served, what was left over and what you had to throw away. Also note the purchase value of spoiled products.
Calculate total waste costs
Add up: (leftover portions × cost per portion) + value of spoiled products + estimated value of leftovers on plates. This gives you the total waste costs of the event.
Divide by number of guests
Divide the total waste costs by the actual number of guests who ate. This gives you the waste costs per person. Compare this with your benchmark of €1.50-€3.00 per person.
✨ Pro tip
Track your waste costs for 6 consecutive running dinners, then compare your highest and lowest nights. The difference between them shows your potential monthly savings - often €200-500 for most operations.
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 include leftovers on plates in the calculation?
Yes, leftovers are also waste. Estimate what percentage of the food is typically left on plates and include this as waste costs.
What if I sell leftovers the next day?
Then you only count the difference. If you have leftovers worth €100 and get €30 for them the next day, your actual waste is €70.
How much waste is normal at a running dinner?
Between €1.50-€3.00 per person is common. This amounts to 8-15% of your total food cost. Above €3.50 per person is too much and costs you profit.
How often should I calculate this?
At every running dinner you organize. After 5-10 events you'll see patterns and be able to estimate better.
📚 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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