Most restaurant owners assume they're serving 100% of what they purchase, but that's rarely the case. Between trimming, cooking shrinkage, and waste, you're often losing 15-30% before food reaches the plate. Here's how to calculate your actual loss percentage and identify where those costly disappearances happen.
What is total loss percentage?
Total loss percentage measures the gap between what you buy and what actually lands on plates. It breaks down into three main areas:
- Trimming loss: what's removed during prep (bones, skins, unusable parts)
- Cooking loss: weight lost through evaporation, rendering, shrinkage
- Waste: spoiled items, over-portioning, leftovers that can't be used
The calculation is straightforward: Total loss percentage = (Purchased weight - Served weight) / Purchased weight × 100
💡 Example:
You buy 10 kg of salmon and serve 6.5 kg to customers:
- Purchased: 10 kg
- Served: 6.5 kg
- Loss: 3.5 kg
Loss percentage: (3.5 / 10) × 100 = 35%
Breaking down the three loss sources
1. Trimming loss (15-50%)
This happens during cleaning and portioning. Whole fish typically loses 40-50%, beef cuts lose 15-25%, fresh vegetables lose 10-20%.
2. Cooking loss (5-20%)
Heat causes weight reduction through moisture loss and fat rendering. Grilled meat shrinks by 15-25%, boiled vegetables by 10-15%.
3. Waste (2-10%)
Items that spoil, get over-portioned, or remain unsold after service. Something most kitchen managers discover too late is that waste often spikes during busy periods due to rushed prep and over-ordering.
⚠️ Note:
Loss percentages don't simply add together. They compound through each stage. 20% trimming loss + 15% cooking loss doesn't equal 35% total loss!
Step-by-step calculation method
For precise numbers, you'll need to track each stage separately:
💡 Complete calculation example:
10 kg whole salmon processed into served portions:
- Purchase: 10.0 kg
- After filleting: 6.0 kg (40% trimming loss)
- After grilling: 5.1 kg (15% cooking loss)
- Actually served: 4.8 kg (6% waste)
Total loss percentage: (10.0 - 4.8) / 10.0 × 100 = 52%
How losses impact your actual costs
With 52% loss, you're paying more than double your purchase price per served portion. If salmon costs €20/kg at purchase, your real cost becomes €20 / 0.48 = €41.67/kg for what reaches the plate.
This explains why many restaurants struggle with food costs. They price based on purchase costs, not the true cost after losses.
💡 Real-world impact:
Restaurant calculation: salmon fillet €20/kg, 200g portion = €4.00 food cost
Actual cost: after 52% loss, 200g served salmon costs €8.33
Annual impact: €4.33 difference × 50 portions/week = €11,258 per year
Typical loss percentages by product category
Standard loss ranges you can expect:
- Whole fish: 45-55% total loss
- Beef (whole cuts): 30-40% total loss
- Whole chicken: 35-45% total loss
- Seasonal vegetables: 20-35% total loss
- Potatoes: 25-30% total loss
- Pre-processed items: 10-20% total loss
These are starting points, but you'll want to measure your own kitchen's performance. Every chef's techniques and supplier quality varies.
How do you calculate total loss percentage? (step by step)
Measure purchase weight exactly
Weigh all products upon arrival and note the total weight. Also include by-products that you discard (boxes and packaging don't count). Use an accurate kitchen scale.
Track each loss step
Weigh after each processing step: after cleaning, after portioning, after cooking. Also note what you discard due to spoilage or mistakes. Keep track of this for a week for reliable averages.
Measure actually served weight
Weigh what actually goes on the plates, not what you think you serve. Add up all portions of one product and compare with your purchase weight. Calculate the loss percentage using the formula.
✨ Pro tip
Track your loss percentages during both slow Tuesday lunch and busy Saturday dinner service over the same week. The difference often reveals 8-12% higher losses during peak times due to rushed prep and portion inconsistency.
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 measure loss percentage for every single ingredient?
Start with your top 10 ingredients by cost - they typically represent 80% of your food spend impact. Once you've got those dialed in, you can expand to other items. Measuring everything at once becomes overwhelming and less accurate.
How often should I recalculate these percentages?
Check quarterly, especially when seasons change or you switch suppliers. Your chef's techniques evolve, ingredient quality shifts, and equipment ages. What you measured six months ago might be off by 5-10% now.
Can I just use industry averages instead of measuring myself?
Industry averages can be off by 5-15% from your actual numbers. At €500,000 annual revenue, that error costs you €25,000-75,000. One week of careful measuring beats months of guessing.
What's the fastest way to track losses during busy service?
Set up pre-weighed containers and have your prep cook record weights at each stage. Don't try to measure during dinner rush - prep time gives you cleaner data without slowing service.
My loss percentage seems higher than average - what's wrong?
Check your measuring technique first, then examine three areas: supplier quality, prep techniques, and inventory turnover. Often one of these three holds the key to reducing losses by 5-10%.
How do I factor loss percentage into menu pricing?
Divide your purchase price by the yield percentage (100% minus loss). If you lose 40% and pay €10/kg, your true cost is €10 ÷ 0.60 = €16.67/kg. Price your menu based on this real cost, not the invoice price.
📚 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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