Most restaurants assume bulk buying automatically saves money. But calculating true portion costs from bulk purchases requires factoring in trim loss, packaging waste, and spoilage. Get the math wrong and your food costs spiral out of control.
The basic calculation: from bulk to portion
The formula looks straightforward: divide total price by portions. Reality's messier due to losses and waste.
💡 Example:
You buy 10 kg of beef for €180 (€18/kg). You want 200 gram portions.
- Theoretically: 10 kg = 50 portions of 200g
- Price per portion: €180 / 50 = €3.60
But this ignores trim loss...
Including trim loss in your calculation
Meat, fish and vegetables always have loss from trimming, bones, peels. This pushes your actual portion price higher.
Formula with trim loss:
Portion price = (Bulk price / Usable weight) × Portion weight
💡 Example beef:
10 kg beef for €180, after trimming 8.5 kg remains (15% loss):
- Actual price per kilo: €180 / 8.5 kg = €21.18/kg
- Portion price 200g: €21.18 × 0.2 = €4.24
Difference: €4.24 vs €3.60 = €0.64 per portion!
Typical trim loss per product
Factor in these average loss percentages:
- Beef (whole cut): 10-20% from fat and sinew
- Fish (whole): 40-55% from head, bones, skin
- Chicken (whole): 25-35% from bones, skin
- Vegetables: 15-25% from peels, bad parts
- Potatoes: 15-20% from peels, eyes
⚠️ Note:
These percentages are guidelines. Measure several times yourself to determine your own loss. This varies by supplier and season.
Packaging loss and dehydration
Even after processing you'll lose weight from dehydration and packaging. Add an extra 2-5% loss to your calculation.
💡 Complete calculation:
10 kg beef, €180, for 180g portions:
- After trimming: 8.5 kg (15% loss)
- After portioning/storage: 8.1 kg (5% extra loss)
- Number of portions: 8.1 kg / 0.18 kg = 45 portions
- Price per portion: €180 / 45 = €4.00
Storage and shelf life
Bulk purchasing means accounting for spoilage. Not everything gets used before expiration.
- Fresh products: 2-7 days shelf life
- Frozen: longer shelf life, but quality drops
- Plan your menu so you use everything
Most kitchen managers discover too late that spoilage can wipe out bulk savings entirely - track your actual usage rates for 30 days before committing to larger orders.
Bulk purchasing makes sense when
Bulk buying pays off when:
- You get a discount of at least 10-15%
- You'll use the product before expiration
- You have sufficient storage space
- Your cash flow can handle larger upfront costs
⚠️ Note:
Always calculate whether bulk discounts outweigh spoilage risk. A product that spoils 20% of the time negates all savings.
Tracking portion costs digitally
Tools like KitchenNmbrs let you compare different purchase prices and suppliers. You'll immediately see actual portion prices after all losses.
This helps with:
- Comparing bulk vs. small quantities
- Tracking your own trim loss percentages
- Automatically calculating food costs
How do you calculate the portion price from bulk purchasing?
Measure your actual yield
Buy a test batch and measure how much usable product you have left after processing. This is your yield percentage (100% minus trim loss%).
Calculate the actual price per kilo
Divide your purchase price by the usable weight. So: bulk price / (purchase weight × yield%). This is your actual cost price per kilo.
Calculate for portion weight
Multiply the actual price per kilo by your desired portion weight in kg. A 200 gram portion = 0.2 kg.
✨ Pro tip
Test your trim loss percentages with 3 different deliveries from each supplier over 2 weeks. Some consistently deliver better quality with 5-8% less waste, justifying higher purchase prices.
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
Should I include VAT in my portion price calculation?
No, your supplier doesn't charge VAT if you're a business. The price you pay is already VAT-exclusive, so use it directly for food cost calculations.
How do I know if bulk purchasing is really cheaper?
Compare actual portion prices after all losses. If bulk is 15% cheaper but you have 10% more loss, it only saves 5%. Factor in spoilage and storage costs too.
What if I don't know exactly how much loss I have?
Start with average percentages from this guide and measure yourself several times. After 3-4 deliveries you'll know your own loss percentage accurately.
Can I compare different suppliers this way?
Yes, but always calculate through to actual portion price. Supplier A might look cheaper, but lower quality means more loss and higher costs.
How often should I recalculate my portion price?
With every supplier price change, and at least monthly. Meat and fish prices change weekly, especially for seasonal products.
Does freezing bulk products affect my portion costs?
Freezing reduces spoilage but adds freezer burn loss (2-8%) and quality degradation. Factor this into your calculations - frozen isn't always cheaper.
Should I negotiate different bulk tiers with suppliers?
Absolutely. Many suppliers offer 5kg, 10kg, and 20kg pricing tiers. Calculate break-even points for each tier based on your actual usage patterns.
📚 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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