The right inventory size determines your cashflow and prevents waste. Too much inventory freezes your money, too little means sold-out dishes and unhappy guests. Here's how to calculate the optimal inventory size for your restaurant type.
Why inventory size is crucial for your profit
Inventory is money tied up in your cooler and storage. Too much inventory means:
- Money you can't spend on other things
- More risk of spoilage and waste
- Higher cooling costs
- Less space in your kitchen
Too little inventory means:
- Sold-out dishes during busy times
- Stress and improvisation in the kitchen
- Disappointed guests
- Lost revenue
⚠️ Note:
Many restaurant owners order by gut feeling or keep too much buffer. That costs you an average of 15-25% more than necessary.
The basic formula for optimal inventory
The formula for optimal inventory size is:
Optimal inventory = (Average daily consumption × Delivery time in days × Safety factor) + Buffer for peaks
💡 Example:
Restaurant with 80 covers per day, salmon as main ingredient:
- Consumption: 40 salmon portions per day × 180g = 7.2 kg/day
- Fish delivery time: 2 days
- Safety factor: 1.3 (30% buffer)
- Peak buffer: 20% extra for weekend
Optimal salmon inventory: (7.2 × 2 × 1.3) + 20% = 22.5 kg
Different factors per restaurant type
Each restaurant type has different inventory needs:
Fine dining:
- Smaller volumes, more variety
- Higher safety factor (1.4-1.6) due to specialties
- Shorter shelf life of premium ingredients
Casual dining/bistro:
- More stable volumes, less variety
- Standard safety factor (1.2-1.4)
- Longer shelf life of basic ingredients
Fast casual/delivery:
- High volumes, limited variety
- Lower safety factor (1.1-1.3) due to predictability
- More focus on shelf-stable products
💡 Example calculation pizzeria:
150 pizzas per day, mozzarella consumption:
- Consumption: 150 pizzas × 120g = 18 kg mozzarella/day
- Delivery time: 1 day (daily fresh delivery)
- Safety factor: 1.2 (predictable demand)
- Weekend peak: +30%
Optimal inventory: (18 × 1 × 1.2) + 30% = 28 kg mozzarella
ABC analysis for your ingredients
Not all ingredients are equally important. From analyzing actual purchasing data across different restaurant types, you'll want to divide them into three categories:
A-ingredients (80% of your purchasing value):
- Meat, fish, premium products
- Precise calculation with low safety factor
- Frequent delivery (2-3x per week)
B-ingredients (15% of your purchasing value):
- Vegetables, dairy, basic products
- Standard calculation with normal safety factor
- Regular delivery (2x per week)
C-ingredients (5% of your purchasing value):
- Spices, garnishes, specialty products
- Larger inventory allowed
- Less frequent delivery (1x per week)
Taking seasons and peaks into account
Your inventory calculation must account for:
- Weekly patterns: Friday/Saturday often 40-60% busier
- Seasons: Summer/winter differences, holidays
- Events: Local events, vacation periods
- Trends: New dishes, seasonal menus
💡 Practical example:
Beach restaurant in summer:
- Normal day: 120 covers
- Sunny Saturday: 300 covers (+150%)
- Rainy day: 40 covers (-67%)
Safety factor: 1.8 for weather-sensitive products like salad
Digital tools for inventory management
Manual inventory tracking takes a lot of time and causes errors. Digital systems help by:
- Automatically calculating daily consumption
- Warning you when inventory is low
- Using historical data for better forecasts
- Linking to your recipes and food cost
Systems track your recipes and ingredient consumption, so you know exactly how much you need without manual counting.
⚠️ Note:
No system predicts perfectly. Use digital tools as a foundation, but adjust based on your experience and local conditions.
Costs of wrong inventory size
Too much inventory costs you directly:
- Tied-up capital: €10,000 inventory costs you €500/year in interest (5%)
- Spoilage: 5-15% of your inventory is lost
- Storage costs: Cooling, space, insurance
Too little inventory costs you revenue:
- Sold-out dishes: Lost sales
- Emergency purchases: Higher prices for rush delivery
- Reputation damage: Disappointed guests won't return
How do you calculate optimal inventory size? (step by step)
Analyze your daily consumption
Look at your sales data from the last 4 weeks. Count how many portions you sold per dish and work backwards to ingredient consumption. Take the daily average.
Determine your delivery times per supplier
Note for each supplier: how many days between order and delivery? Add 1 day for safety (delays, out of stock at supplier).
Calculate your safety factor per product group
A-products (expensive): factor 1.2-1.3. B-products (basic): factor 1.3-1.4. C-products (cheap): factor 1.5-2.0. Higher factor for unpredictable demand.
Add peak buffer for busy times
Calculate how much busier your weekends/holidays are. Add 20-50% buffer depending on your peaks and whether you can reorder in between.
Test and adjust based on experience
Start with your calculation and monitor for 2-4 weeks. Frequently sold out? Increase buffer. Too much spoilage? Lower safety factor. Adjust until it works.
✨ Pro tip
Track your inventory turnover ratio weekly for the past 8 weeks - if it's consistently below 12 times per year, you're carrying too much stock. Cut your safety factors by 10% and monitor for stockouts.
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
How much inventory is normal for a restaurant?
Do I need to calculate separately for each ingredient?
What if my supplier is unreliable?
How often should I adjust my inventory calculation?
Can I estimate inventory without exact figures?
What do I do with products that spoil quickly?
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
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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