The shelf life of ingredients determines how much you throw away and thus how much profit you lose. Many kitchens have no idea how long products typically last before they go bad. By tracking this systematically, you can buy smarter and drastically reduce waste.
Why calculating shelf life matters
Food waste costs the average kitchen between 5% and 15% of purchases. With an annual turnover of €400,000 and 30% food cost, you're talking about €6,000 to €18,000 per year that literally goes in the trash.
By tracking how long ingredients typically last per product category, you can:
- Buy smarter (smaller quantities of perishable products)
- Apply FIFO (first in, first out) better
- Predict when you need to reorder
- Reduce waste by 30-50%
Organize product categories
Divide your ingredients into these main categories:
💡 Example categories:
- Fresh fish: 1-2 days
- Meat (fresh): 2-4 days
- Vegetables (leafy greens): 3-5 days
- Vegetables (root vegetables): 1-2 weeks
- Dairy: 5-10 days after opening
- Herbs (fresh): 3-7 days
Set up a registration system
Track for each delivery:
- Delivery date: When did it arrive?
- Usage date: When was it used up or thrown away?
- Quantity: How many kilos/pieces?
- Reason for end: Used up, went bad, or past date?
⚠️ Note:
Only count what you actually managed to use. If you buy 5 kilos of potatoes but throw away 1 kilo, the useful shelf life is based on the 4 kilos you used.
Calculate the average
After collecting data for 4-6 weeks, you can calculate the average per category:
Formula: Average shelf life = Sum of all usage days ÷ Number of deliveries
💡 Example calculation fresh fish:
- Week 1: 2 days used
- Week 2: 1 day used (rest thrown away)
- Week 3: 3 days used
- Week 4: 2 days used
Average: (2+1+3+2) ÷ 4 = 2 days
Factor in seasons and suppliers
Shelf life varies by:
- Season: Summer lettuce lasts shorter than winter lettuce
- Supplier: Fresh supplier vs. wholesale can make 1-2 days difference
- Storage: Cooling temperature and humidity affect shelf life
Therefore, keep separate averages for different conditions.
Digital registration vs. paper
Many kitchens start with an Excel sheet or paper list. Disadvantages:
- Forgotten during busy periods
- Manual calculations
- Losing overview with many categories
An app like KitchenNmbrs can help by automatically calculating averages and alerting you when products approach their average shelf life.
✅ Result after 3 months:
Kitchens that systematically track shelf life reduce their food waste by an average of 35%. With €120,000 annual purchases, that saves €6,300 per year.
How do you calculate average shelf life? (step by step)
Create a registration system
Divide your ingredients into categories (fish, meat, vegetables, dairy, etc.). Create a list or Excel sheet where you can track the date, quantity, and when it was used up for each delivery.
Register every delivery for 4-6 weeks
For each delivery, note: delivery date, quantity, and the date the product was used up or thrown away. Also track why (used up or went bad).
Calculate the average per category
Add up all usage days and divide by the number of deliveries. For example: fish was used after 2, 1, 3, and 2 days = (2+1+3+2) ÷ 4 = 2 days average.
Adjust your purchases based on the data
Use the average shelf life to determine how much you should buy maximum. With 2 days average and 50 fish portions per week, it's better to buy twice a week than once.
✨ Pro tip
Start with your 5 most expensive product categories. That's where the biggest savings are. One extra day of shelf life for an expensive product like fresh fish saves more than a week for cheap onions.
Calculate this yourself?
In the KitchenNmbrs app you can do this in just a few clicks. 7 days free, no credit card.
Was this article helpful?
Frequently asked questions
How long should I collect data for a reliable average?
At least 4-6 weeks, but preferably 8-12 weeks. This way you capture different deliveries, seasonal influences, and busy periods in your calculation.
Should I also count products I throw away?
Yes, but register separately why you threw it away. If you systematically overbuy, that gives a skewed picture of the actual shelf life.
What if I have different suppliers for the same product?
Keep separate averages per supplier. Quality can differ significantly between a local grower and wholesale, sometimes 1-2 days difference.
How often should I update my averages?
Check every 3 months whether your averages still hold true. Seasons, new suppliers, or different storage methods can affect shelf life.
Can't I just use the expiration date on the packaging?
That date is often too conservative or too optimistic. Your own kitchen conditions (temperature, humidity, how often the cooler is opened) determine the actual shelf life.
📚 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.
Manage inventory without spreadsheets
Always know what you have in stock and what it's worth. KitchenNmbrs connects inventory to recipes and purchasing for complete oversight. Start your free trial.
Start free trial →