Calculating oysters is more than just the purchase price. You have preparation costs (opening, checking), presentation (ice, lemon, sauces) and loss from broken specimens. Without factoring in these costs, you earn less than you think on this luxury product.
Gather all costs for your oyster portion
An oyster portion consists of more than just the oysters themselves. For an accurate cost price calculation, you add up everything that goes on the plate:
- Oysters themselves (purchase price per piece)
- Presentation: ice, sea salt, lemon wedges
- Garnish: shallot vinegar, tabasco, bread with butter
- Preparation costs: time for opening and checking
- Loss: broken or poor quality specimens
💡 Example portion 6 oysters:
Menu price: €18.50 (incl. 9% VAT) = €16.97 excl. VAT
- 6 oysters at €1.80: €10.80
- Presentation (ice, lemon, shallot): €1.20
- Bread with butter: €0.80
- Preparation time (5 min at €18/hour): €1.50
- Loss 10%: €1.43
Total cost price: €15.73
Food cost: €15.73 / €16.97 = 92.7% - way too high!
Calculate preparation costs realistically
Opening oysters takes time and skill. Factor this in as labor costs:
- Time per portion: 3-5 minutes (depending on experience)
- Kitchen hourly rate: €15-20 per hour (incl. employer contributions)
- Calculation: (Minutes / 60) × Hourly rate
⚠️ Note:
Inexperienced staff takes longer and has more breakage. Start with 6-8 minutes per portion and 15% loss.
Factor in loss and breakage
With oysters you always have loss. Calculate this percentage into your purchase price:
- Broken shells: 5-8% of delivery
- Bad oysters: 2-5% (don't smell right, look poor)
- Total loss: 10-15% is normal
💡 Loss calculation:
You buy 100 oysters for €180 (€1.80 per piece)
12% loss = 88 usable oysters
Actual cost price: €180 / 88 = €2.05 per oyster
Determine your minimum selling price
With all costs known, calculate the minimum selling price for a healthy margin:
- Desired food cost: 25-30% (oysters are a luxury product)
- Formula: Total cost price / (Food cost% / 100)
- Add VAT: × 1.09 for menu price
💡 Price calculation:
Cost price 6 oysters: €14.50
Desired food cost: 28%
Minimum price excl. VAT: €14.50 / 0.28 = €51.79
Menu price: €51.79 × 1.09 = €56.45
Season and quality affect your cost price
Oyster prices fluctuate greatly by season and quality. Keep track of this:
- High season (Sept-April): higher prices, better quality
- Summer months: cheaper but more loss
- Special occasions: Christmas, New Year = peak prices
- Update regularly: check your purchase prices monthly
A system like KitchenNmbrs helps you automatically update your oyster cost prices when your supplier raises prices, including all preparation and presentation costs.
How do you calculate the cost price of oysters? (step by step)
Add up all ingredients
Note the purchase price per oyster, plus all garnish (ice, lemon, shallot vinegar, bread, butter). Don't forget any item that goes on the plate.
Calculate preparation costs
Measure how long opening takes (usually 3-5 minutes per portion). Multiply by your kitchen staff's hourly rate divided by 60.
Factor in loss and breakage
Add 10-15% loss to your purchase price for broken or bad oysters. Divide your total purchase by the number of usable oysters.
Determine your selling price
Divide your total cost price by your desired food cost percentage (25-30% is normal for oysters). Multiply by 1.09 for VAT.
✨ Pro tip
Check with your supplier if you get a discount on whole box purchases. Often the price per piece is lower, but watch that your loss percentage doesn't increase due to longer storage.
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
What loss percentage should I calculate for oysters?
Calculate 10-15% loss from broken shells and bad specimens. In summer this can rise to 20% due to heat.
Should I include preparation time in the cost price?
Yes, opening oysters takes 3-5 minutes of skilled work per portion. Factor this in as labor costs based on your kitchen hourly rate.
How often should I adjust my oyster prices?
Check your purchase prices with your supplier monthly. Oyster prices fluctuate greatly by season and demand, especially around holidays.
What food cost is normal for oysters?
For oysters, 25-30% food cost is standard. It's a luxury product where guests are willing to pay more than for regular dishes.
What do I include in presentation costs?
Include everything: ice for presentation, lemon wedges, shallot with vinegar, tabasco, bread with butter. Also napkins and special oyster plates if you use them.
📚 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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