A yield test reveals the actual cost of your fish fillets by measuring usable meat after processing. You might purchase whole fish at €12/kg, but you're actually paying €24/kg for the fillet once you account for cutting losses. Most kitchens miss this critical calculation.
What is a yield test?
A yield test measures how many kilos of edible meat you extract from a whole fish after filleting. It's the difference between what you buy and what you actually serve.
Your cutting loss includes several components:
- Head (15-20% of total weight)
- Bones and spine (10-15%)
- Skin and fins (5-8%)
- Offal (8-12%)
? Example:
Whole salmon of 3 kg for €36 (€12/kg):
- Head: 0.6 kg
- Bones: 0.4 kg
- Skin: 0.2 kg
- Offal: 0.3 kg
- Usable fillet: 1.5 kg
Real fillet cost: €36 ÷ 1.5 kg = €24/kg
Why yield tests matter for profitability
Too many kitchens calculate costs using purchase price per kilo. That's a recipe for disaster. You buy fish whole but sell it as portioned fillets.
Calculate with €12/kg instead of the real €24/kg? You're losing €12 per kilo. Process 20 kg weekly and you've hemorrhaged €12,480 annually in hidden costs. From years of working in professional kitchens, I've seen restaurants fail because they ignored this fundamental calculation.
⚠️ Note:
Yields fluctuate with suppliers and seasons. Test monthly, not annually.
Expected yields by fish type
Standard yields vary significantly (always test your own!):
- Salmon: 45-55% fillet
- Sea bass: 35-45% fillet
- Dorade: 35-40% fillet
- Cod: 40-50% fillet
- Tuna: 60-70% (headless at purchase)
- Plaice/Sole: 50-60% fillet
? Real numbers:
Sea bass 2 kg for €30 (€15/kg):
- Expected yield: 40%
- Fillet weight: 2 kg × 0.40 = 0.8 kg
- True fillet cost: €30 ÷ 0.8 kg = €37.50/kg
Using €15/kg costs you €22.50 per kilo of fillet!
Integrating yields into cost calculations
Always calculate with actual fillet prices in your recipes:
True cost per kilo = Purchase price ÷ (Yield % ÷ 100)
With 40% yield and €15/kg purchase: €15 ÷ 0.40 = €37.50/kg fillet.
Use €37.50 in your costing, never the €15 purchase price.
? Menu costing example:
Sea bass fillet 180g portion:
- Real fillet cost: €37.50/kg
- Portion cost: 0.18 kg × €37.50 = €6.75
- Menu price €32 (excl. VAT €29.36)
- Fish food cost: €6.75 ÷ €29.36 = 23%
Tracking and documentation
Document every yield test systematically. Record:
- Date and supplier name
- Total purchased weight
- Usable fillet weight
- Calculated yield percentage
- Real cost per kilo of fillet
Test monthly for frequently used fish from each supplier. Seasonal variations can swing yields 5-10% based on fish condition and size.
Food cost calculators can store yield percentages per ingredient, automatically adjusting your recipe costs with real fillet prices instead of purchase prices.
Related articles
How do you perform a yield test? (step by step)
Weigh the whole fish
Weigh the fish immediately upon delivery, including head and offal. Record the total weight and the purchase price per kilo.
Fillet the fish professionally
Have your best chef fillet the fish the way you normally do. Keep all waste separate: head, bones, skin, offal.
Weigh the usable fillet
Weigh only the fillet you can actually sell. Calculate the yield percentage: (fillet weight ÷ total weight) × 100.
Calculate the actual fillet price
Divide the total purchase costs by the fillet weight. This is your actual cost price per kilo of fillet for your recipes.
Update your cost price calculation
Use the actual fillet price in all your recipes with this fish. Check if your menu price is still profitable at the real costs.
✨ Pro tip
Weigh your fish waste separately by category (head, bones, skin) during the first 3 yield tests. This shows you exactly where your losses occur and can improve your filleting technique by 2-3%.
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Frequently asked questions
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Can I rely on online yield percentages?
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Do different suppliers require separate yield tests?
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Does fish size affect yield percentages?
⚠️ 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
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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