Nearly 70% of restaurants underestimate their actual fish costs by ignoring trim loss calculations. You buy salmon at €18 per kilo, but after removing heads, bones, and skin, you're actually paying €30 per kilo for usable fillet. Here's how to calculate the real cost of every fish portion you serve.
What is trim loss in fish?
Trim loss represents the unusable weight you remove during fish preparation. Heads, bones, skin, and fins all contribute to this waste. With whole fish, you'll lose anywhere from 35% to 60% of your purchase weight.
⚠️ Watch out:
Most kitchen managers discover too late that calculating only the purchase price per kilo creates a false sense of profitability. You're actually working with 40-60% of what you bought.
The formula for fish cost price per portion
Break down your calculation into three simple steps:
- Step 1: Calculate the yield (100% - trim loss%)
- Step 2: Determine actual price per kilo after losses
- Step 3: Calculate cost per individual portion
💡 Example whole salmon:
Whole salmon costs €18.00 per kilo. After filleting, you get 1.2 kg fillet from 2 kg whole fish.
- Trim loss: ((2.0 - 1.2) / 2.0) × 100 = 40%
- Yield: 100% - 40% = 60%
- True fillet price: €18.00 / 0.60 = €30.00 per kilo
For a 180 gram portion: €30.00 × 0.18 = €5.40
Typical trim loss per fish type
Different fish species produce varying amounts of usable meat. Use these percentages as your baseline:
- Whole salmon: 35-45% trim loss
- Whole sea bream: 45-55% trim loss
- Whole sole: 50-60% trim loss
- Whole cod: 40-50% trim loss
- Unpeeled shrimp: 40-50% trim loss
- Mussels: 15-25% trim loss (empty shells)
💡 Example shrimp:
Unpeeled shrimp cost €24.00 per kilo. Peeling creates 45% trim loss.
- Yield: 55%
- Actual peeled shrimp price: €24.00 / 0.55 = €43.64 per kilo
- For 120 gram portion: €43.64 × 0.12 = €5.24
Whole fish vs. buying fillets
Sometimes pre-cut fillets offer better value than whole fish. Compare both options systematically:
- Whole fish: Purchase price / yield = actual fillet cost
- Ready fillets: Direct purchase price
- Whole fish drawback: Labor time for filleting
- Whole fish benefit: Bones and heads for stock production
💡 Salmon comparison:
Whole salmon €18/kg (60% yield) vs. salmon fillet €28/kg
- Whole salmon after losses: €18 / 0.60 = €30/kg
- Pre-cut fillet: €28/kg
- Fillet wins: €2/kg cheaper + saves prep time
Including additional costs
Trim loss isn't your only hidden expense. Factor in these additional costs:
- Labor time: Filleting requires skill and time (€20-25 per hour)
- Waste factor: Mistakes and spoilage (add 5-10% buffer)
- Storage limits: Fresh fish deteriorates within 2-3 days
- Seasonal pricing: Costs fluctuate dramatically throughout the year
⚠️ Watch seasonal swings:
Fish prices swing 30-50% based on season and availability. Update your calculations regularly, particularly for seasonal varieties like sole or eel.
Tracking fish prices digitally
Managing trim calculations and price fluctuations manually becomes overwhelming quickly. Digital tools can automate these complex calculations for you.
Food cost calculators automatically compute actual portion costs including all losses. You input purchase prices and trim percentages, then get accurate cost data without manual errors.
How do you calculate fish cost price per portion? (step by step)
Measure the actual trim loss
Weigh the whole fish before processing and then weigh only the usable meat. Calculate the trim loss: ((whole fish - usable meat) / whole fish) × 100. Do this a few times for a reliable average.
Calculate the actual price per kilo
Divide the purchase price by the yield percentage. Yield = 100% - trim loss%. For example: €18/kg at 40% trim loss = €18 / 0.60 = €30/kg actual price.
Calculate per portion
Multiply the actual price per kilo by the weight per portion in kilograms. For 180 gram portion: €30 × 0.18 = €5.40 per portion. Optionally add 5-10% for waste.
✨ Pro tip
Weigh and measure 5-6 whole fish of each type over a 2-week period to establish your average trim loss percentage. This baseline eliminates guesswork and gives you reliable data for future purchasing decisions.
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 labor time for filleting in my cost calculations?
Absolutely, especially with premium fish. Calculate roughly €20-25 per hour for filleting time. This cost matters more with expensive fish than budget varieties.
How often should I update my fish price calculations?
Check with suppliers weekly to verify current pricing. Fish markets change rapidly due to weather, seasons, and availability. Update immediately if prices shift more than 10%.
What should I do with bones and heads from whole fish?
Turn them into fish stock and calculate that value (approximately €2-3 per kilo). Subtract this revenue from your trim loss calculations to get true net cost.
⚠️ EU Regulation 1169/2011 — Allergen Information — https://eur-lex.europa.eu/eli/reg/2011/1169/oj
The allergen information on this page is based on EU Regulation 1169/2011. Recipes and ingredients may vary by supplier. Always verify current allergen information with your supplier and communicate this correctly to your guests. KitchenNmbrs is not liable for allergic reactions.
In the UK, the FSA enforces allergen regulations under the Food Information Regulations 2014.
📚 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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