Alternative fish species can save your margin when your main supplier runs out of stock or prices spike overnight. Each fish has different cost prices, cutting losses, and portion weights that directly impact your bottom line.
Why alternative fish matters for your margin
Fish markets are volatile. Salmon jumps from €18 to €26 per kilo in a week. Your supplier's out of sole but has fresh plaice. Without preparation, you're flying blind on food costs.
Each fish species brings unique challenges:
- Different purchase prices per kilo
- Different cutting loss (fillet vs. whole)
- Different portion weights (200g salmon vs. 180g sea bass)
- Different cooking losses
Calculate the actual kilo price per fish species
Start here: what does each fish actually cost per kilo after processing?
💡 Example: Salmon vs. Sea Bass
Salmon (fillet):
- Purchase price: €22/kg
- Cutting loss: 5% (already filleted)
- Actual price: €22 ÷ 0.95 = €23.16/kg
Sea bass (whole):
- Purchase price: €16/kg
- Cutting loss: 45% (head, bones, skin)
- Actual price: €16 ÷ 0.55 = €29.09/kg
Salmon wins despite the higher purchase price!
⚠️ Note:
Always calculate with cutting loss. Divide purchase price by yield (100% - loss%). Multiplying gives you wrong numbers!
Calculate cost price per portion for each fish species
Now you've got the real kilo price. Calculate portion costs, accounting for different weights per species.
💡 Example: Cost price per portion
Salmon (200g portion):
- Actual price: €23.16/kg
- Cost price: 0.2 kg × €23.16 = €4.63 per portion
Sea bass (180g portion):
- Actual price: €29.09/kg
- Cost price: 0.18 kg × €29.09 = €5.24 per portion
Don't forget garnish, sauce and cooking oil.
Compare total food cost including side dishes
Fish alone doesn't make a dish. Add everything for accurate comparison. This is the kind of thing you only learn after closing your first month at a loss - every ingredient counts.
- Main ingredient (fish)
- Garnish (vegetables, potatoes)
- Sauces and butter
- Oil for cooking
- Seasonings and decoration
💡 Example: Complete cost price
Salmon dish:
- Salmon: €4.63
- Vegetables: €1.20
- Sauce: €0.85
- Oil/butter: €0.32
Total: €7.00
Sea bass dish:
- Sea bass: €5.24
- Vegetables: €1.20
- Sauce: €0.85
- Oil/butter: €0.32
Total: €7.61
Calculate food cost at different menu prices
Now you can determine which alternative delivers better margins at your current menu price.
Formula: Food cost % = (Ingredient costs ÷ Selling price excl. VAT) × 100
💡 Example: At €28.50 menu price
Selling price excl. 9% VAT: €28.50 ÷ 1.09 = €26.15
Salmon:
- Food cost: (€7.00 ÷ €26.15) × 100 = 26.8%
Sea bass:
- Food cost: (€7.61 ÷ €26.15) × 100 = 29.1%
Salmon gives you 2.3 percentage points better margin.
Create an overview of your fish alternatives
Document these details for your 3-5 most common fish species:
- Purchase price per kilo
- Cutting loss percentage
- Actual kilo price
- Standard portion weight
- Cost price per portion
Update monthly or whenever prices shift significantly. You'll be ready to pivot quickly when your supplier delivers bad news.
⚠️ Note:
Always inform guests about species substitutions. Some have allergies or preferences. Transparency prevents complaints.
Digital tracking saves time and errors
Manual calculations eat time and invite mistakes. Systems like tools like KitchenNmbrs automatically track portion costs for each fish species, including all accompaniments.
You instantly see which alternatives stay profitable at your menu price. Perfect for those emergency supplier calls.
How do you calculate the margin on alternative fish? (step by step)
Calculate actual kilo price per fish species
Divide the purchase price by the yield (100% minus cutting loss). For example: €16/kg at 45% loss = €16 ÷ 0.55 = €29.09/kg actual.
Determine cost price per portion including side dishes
Multiply actual kilo price by portion weight, add garnish, sauce and oil. For example: 180g × €29.09 + €2.37 side dishes = €7.61 total.
Calculate food cost percentage at your menu price
Divide total ingredient costs by selling price excl. VAT, multiply by 100. Compare all alternatives and choose the lowest food cost.
✨ Pro tip
Track your top 4 fish alternatives weekly for 6 weeks to identify price patterns. You'll spot which species stays most stable and can serve as your reliable backup option.
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
Do I need to calculate a different cutting loss for each fish species?
Absolutely. Whole fish loses 40-55%, fillets only 5-10%. Unpeeled shrimp drops 35-50%, peeled barely any. Wrong percentages mean wrong cost calculations.
Can I just pick the fish with the lowest purchase price?
Never. Look at actual price after processing losses. Whole fish appears cheap but wastes heavily. Fillets cost more upfront but yield better value.
Should I use different portion weights per fish species?
You can if it makes sense. Serve 200g of dense salmon, 180g of lighter fish. But stay consistent per species for accurate cost calculations.
⚠️ 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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