A single weekend with unexpected overtime can turn a profitable week into a breakeven one. Prime cost typically runs 55-65% of revenue, but overtime pushes this number higher fast. Here's how to calculate exactly what those extra hours cost you.
What is prime cost and why is overtime so expensive?
Prime cost combines your food cost (ingredients) plus labor cost (staff). Overtime hits hard because you're paying 150% or 200% of regular rates.
💡 Example:
Normal situation this week:
- Revenue: €8,000
- Food cost: €2,400 (30%)
- Labor cost: €2,000 (25%)
Prime cost: €4,400 (55%)
Calculate your normal labor cost per week
Pull your staff schedule and total all regular hours. Multiply each employee's hours by their hourly rate. This gives you baseline labor cost.
- Chef: 40 hours × €18 = €720
- Sous chef: 38 hours × €15 = €570
- Service: 60 hours × €12 = €720
- Dishwashing: 20 hours × €11 = €220
Total normal labor cost: €2,230
Add up all overtime and calculate the extra costs
Most overtime runs 150% of standard rate. But check your employment contracts — some collective agreements differ.
💡 Overtime example:
Extra hours this week:
- Chef: 8 overtime hours × €18 × 1.5 = €216
- Service: 12 overtime hours × €12 × 1.5 = €216
Extra overtime costs: €432
⚠️ Note:
Don't forget employer contributions (approximately 25% extra). So overtime costs you even more than just the overtime rate.
Calculate your new prime cost percentage
Add food cost plus total labor cost (regular + overtime). Divide by revenue and multiply by 100 for the percentage.
Formula: Prime cost % = ((Food cost + Total labor cost) / Revenue) × 100
💡 Calculation:
With overtime:
- Food cost: €2,400
- Normal labor cost: €2,230
- Overtime: €432
- Employer contributions on overtime: €108
New prime cost: €5,170 (64.6%)
What does this mean for your profit?
The jump from 55% to 64.6% prime cost equals almost 10 percentage points. On €8,000 revenue, that's €770 less profit for the week.
Annually, with an average of 8 overtime hours weekly:
- Extra costs per week: €540 (including employer contributions)
- Per year: €540 × 52 = €28,080
- That's more than hiring another full-time employee!
From tracking this across dozens of restaurants, the pattern stays consistent — every 4 hours of weekly overtime typically adds 2-3 percentage points to prime cost.
How do you prevent unnecessary overtime?
The cheapest overtime is zero overtime. Review these points weekly:
- Schedule staff based on forecasted busy periods
- Track which days consistently need overtime
- Consider hiring part-timers for peak days
- Train your team for better efficiency
💡 Practical tip:
Keep an overtime log. Note why the overtime happened. You'll spot patterns and can fix recurring issues.
Tools that help with tracking
Manually tracking labor costs and overtime eats up time. A food cost calculator like KitchenNmbrs helps you quickly calculate prime cost and see overtime's impact at a glance.
How do you calculate the impact of overtime on your prime cost?
Gather your basic data
Note your weekly revenue, food cost, and normal labor cost. These are your starting points for the calculation.
Calculate the cost of all overtime
Add up all overtime hours and multiply by 150% of the normal hourly rate. Don't forget employer contributions (approximately 25% extra).
Calculate your new prime cost percentage
Add food cost and total labor cost, divide by revenue and multiply by 100. Compare with your normal prime cost to see the impact.
✨ Pro tip
Track your overtime costs every Monday for the past 7 days and calculate the exact impact on prime cost percentage. After 4 weeks, you'll see patterns that cost you thousands annually.
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 is a normal prime cost for restaurants?
Typical prime cost runs 55-65% of revenue. Below 55% is excellent performance, above 70% starts hurting profitability seriously.
How often do I have to pay 150% for overtime?
This depends on your collective agreement and employment contracts. Many hospitality agreements kick in 150% after 40 hours weekly, but always verify your specific agreements.
Can I avoid overtime by hiring more part-time staff?
Usually yes. Two part-timers at 20 hours each typically cost less than one full-timer with 8 overtime hours. Plus you get more scheduling flexibility.
Should I include employer contributions in my prime cost?
Absolutely — employer contributions are real costs you pay. Calculate roughly 25% extra on top of gross salary for pension, insurance, and vacation pay.
📚 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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