Gross purchases and net consumption are two different ways to look at your inventory. Gross purchases is what you order and pay for, net consumption is what actually ends up on your guests' plates. The difference between these two numbers shows you where your money is leaking without you realizing it.
What is gross purchases?
Gross purchases is the total value of all products you buy. This is the amount on your invoices and what you pay your suppliers.
- Whole salmon of 2 kg for €36
- 10 kg potatoes for €8
- 5 liters cream for €15
Your gross purchases is simple to calculate: add up all your purchase invoices.
💡 Example:
Restaurant De Smulhoek purchases this week:
- Meat and fish: €1.200
- Vegetables: €400
- Dairy: €300
- Other: €200
Gross purchases: €2.100
What is net consumption?
Net consumption is the actual value of ingredients that end up on your guests' plates. This is always lower than your gross purchases because of:
- Cutting loss: bones, skin, fat, trimmings
- Waste: spoiled products, mise-en-place that gets thrown away
- Staff consumption: staff meals
- Tasting and testing: chef tastes while cooking
💡 Example:
From that €2.100 gross purchases, the following is lost:
- Cutting loss fish: €180 (15%)
- Vegetable waste: €40 (10%)
- Staff meals: €150
- Other loss: €80
Net consumption: €2.100 - €450 = €1.650
Why this difference matters
The difference between gross purchases and net consumption shows you hidden costs - costs you incur but don't directly see in your dishes.
⚠️ Watch out:
Many entrepreneurs only calculate with gross purchases for their food cost. Then your food cost looks lower than it really is. You lose money without knowing it.
In the example above:
- Gross purchases: €2.100
- Net consumption: €1.650
- Difference: €450 (21% loss!)
This €450 isn't in your dishes, but you pay for it anyway. That's €1.800 per month in extra costs you don't see back.
How do you calculate the difference?
The formula is simple:
Loss percentage = ((Gross purchases - Net consumption) / Gross purchases) × 100
💡 Example calculation:
Gross purchases: €2.100
Net consumption: €1.650
Loss: ((€2.100 - €1.650) / €2.100) × 100 = 21.4%
For every €100 you purchase, €78.60 ends up on the plates.
Typical loss percentages
Every restaurant has loss, but the amount varies:
- Well-managed kitchen: 15-20% loss
- Average kitchen: 20-25% loss
- Poorly managed kitchen: 25-35% loss
Above 25% loss costs you a lot of money. Every 5% improvement saves hundreds of euros per month.
Where does it go wrong?
The biggest loss items are often:
- Underestimated cutting loss: whole fish has 40-50% loss, not 20%
- No FIFO: old products get thrown away, new ones stay
- Over-portioning: chef gives more than calculated
- Poor storage: products spoil faster
⚠️ Watch out:
If you don't know your net consumption, you can't calculate accurate food cost. Your food cost will then look lower than it really is.
How do you get control of the difference?
Step 1 is to measure. You can't improve what you don't measure:
- Count your inventory weekly (beginning and end of week)
- Keep track of what you throw away and why
- Measure cutting loss on large products (fish, meat)
- Register staff meals
With a system like KitchenNmbrs you can track this digitally. You immediately see the difference between what you purchase and what is actually consumed.
How do you calculate the difference between gross purchases and net consumption?
Add up your total gross purchases
Get all your purchase invoices from a week and add them up. This is your gross purchases - the amount you actually paid to suppliers.
Calculate your net consumption
Subtract all loss items from your gross purchases: cutting loss, waste, staff meals and other loss. This gives you net consumption.
Calculate the loss percentage
Use the formula: ((Gross purchases - Net consumption) / Gross purchases) × 100. This percentage shows how much of your purchases doesn't end up on the plates.
✨ Pro tip
Measure precisely for one week what you throw away and why. Write everything down: spoiled lettuce, incorrectly cut meat, leftover mise-en-place. This immediately gives you insight into your biggest loss items.
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 loss percentage between gross purchases and net consumption?
A well-managed kitchen has 15-20% loss. Above 25% becomes expensive and indicates there's a lot of room for improvement in your inventory management.
Should I count staff meals as loss?
Yes, staff meals are costs that aren't paid for by guests. Count them as loss, but keep them separate so you know how much this costs.
How often should I calculate this difference?
At least monthly, but weekly gives you more control. That way you see faster if your loss is increasing and can adjust before it costs you a lot of money.
Can I calculate my food cost without knowing net consumption?
You can, but then your food cost won't be accurate. You'll calculate with costs that are too low and earn less than you think. Net consumption gives you the real costs.
What if my loss percentage is higher than 25%?
Then a lot of money is leaking away. Focus first on the biggest loss items: cutting loss on expensive products and waste. Every 5% improvement saves hundreds of euros per month.
📚 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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