Does your restaurant make €15,000 per week in summer but only €8,000 in January? Understanding your true base revenue versus seasonal spikes prevents costly mistakes. Here's how to separate the two for smarter business decisions.
Why separate base revenue and seasonal revenue?
Without knowing what's pure seasonality, you'll make wrong choices. You might think you're growing structurally when it was just summer weather. Or panic in January when that's simply normal for your business type.
- You hire too many staff for winter months
- You order excessive inventory during quiet periods
- You raise prices when the real issue is seasonality
- You create overly optimistic budgets
The 3-year method: your most reliable foundation
The simplest approach? Look at three years of data. Compare identical weeks or months across different years.
💡 Example:
Beach bar - week 30 (late July):
- 2022: €18,500
- 2023: €19,200
- 2024: €20,100
Average summer week: €19,267
Same bar - week 5 (early February):
- 2022: €3,200
- 2023: €3,800
- 2024: €4,100
Base revenue (winter): €3,700 per week
The baseline formula
Your base revenue equals what you earn during your worst structural month. Not incidents like renovations or lockdowns - just regular quiet season.
Base revenue formula:
Base revenue = Average of your 3 lowest months (excluding incidents)
💡 Example bistro:
Monthly revenue 2024:
- January: €28,000
- February: €26,500
- March: €31,000
- December: €27,200
Base revenue: (€28,000 + €26,500 + €27,200) / 3 = €27,233 per month
Calculate seasonal factor
Once you've identified your base revenue, calculate what percentage of seasonality each month carries.
Seasonal factor = (Actual revenue / Base revenue) × 100
💡 Example terrace restaurant:
Base revenue: €35,000/month
- July revenue: €52,000
- Seasonal factor: (€52,000 / €35,000) × 100 = 149%
July performs 49% above base due to seasonality
Structural growth vs. seasonal growth
From years of working in professional kitchens, I've seen owners confuse seasonal spikes with real growth. Here's the difference:
- Structural growth: your base months rise consistently
- Seasonal growth: only peak months increase
- Real growth: both rise, with base months showing improvement
⚠️ Watch out:
If only summer months grow while winter months stagnate, you don't have structural growth. You just benefited from good weather or local events.
Practical application for your planning
Armed with these numbers, you can make smarter decisions:
- Staff: Plan core team around base revenue, seasonal workers on the factor
- Purchasing: Stock for base revenue plus seasonal inventory
- Cashflow: Save seasonal profits for quiet months
- Investments: Calculate returns using base revenue, not peak months
💡 Example staffing plan:
Restaurant with base revenue €40,000/month:
- Fixed staff: €12,000/month (30% of base)
- July (factor 140%): €40,000 × 1.4 = €56,000 revenue
- Extra staff July: (€56,000 - €40,000) × 30% = €4,800
Total staff costs July: €16,800
Track seasonal data digitally
Excel works, but it's time-consuming. A food cost calculator like KitchenNmbrs can track monthly revenue data and automatically calculate seasonal factors. You'll immediately see whether growth is structural or seasonal.
How do you calculate base revenue vs seasonal revenue?
Collect 3 years of revenue data per month
Get your revenue figures from the last 3 years. Note the total revenue per month. Exclude incidental months (renovation, corona, special events).
Determine your 3 lowest months on average
Find your 3 structurally lowest months per year. Add them up and divide by 3. This is your base revenue - what you earn without seasonal advantage.
Calculate seasonal factor per month
Divide each month's revenue by your base revenue and multiply by 100. Above 100% is seasonal advantage, below 100% is seasonal dip.
Check if growth is structural
Compare your base months this year with last year. Only if those are also rising do you have real structural growth instead of just seasonal luck.
✨ Pro tip
Calculate your seasonal factor for the past 24 months and set aside exactly 35% of above-baseline revenue during peak periods. This creates a reliable cash buffer for slower months without guessing.
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 have 3 years of data yet?
Use whatever data you have, but draw more cautious conclusions. One year shows seasonal patterns but not whether they're reliable. Build your database gradually and adjust expectations as you gather more information.
How often should I recalculate my base revenue?
At least once yearly, after your slowest season ends. If you make major changes like renovations or concept shifts, recalculate immediately since your new baseline will differ significantly.
What if my seasonal pattern changes due to climate?
Climate change disrupts traditional patterns more frequently. Warm winters and cool summers throw off historical data. Use 5-year averages and adjust expectations to match new weather realities rather than clinging to outdated patterns.
Can I do this weekly instead of monthly?
Absolutely, and it provides more precise insights. Weekly analysis works especially well for highly seasonal businesses like beach bars or ski resorts. Use consistent week numbers across multiple years for accurate comparisons.
📚 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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