Over 60% of restaurants lose money on desserts simply because they're serving portions that are too large for their cost structure. Many establishments guess at portion sizes, causing them to unknowingly lose money or disappoint guests with portions that are too small. Here's how to calculate the optimal portion weight based on your purchase price and desired margin.
Why portion weight matters so much
With desserts, portioning often goes wrong. A tiramisu of 120 grams instead of 100 grams seems like a small difference, but costs you an extra €0.80 per portion. With 200 desserts per week, you're losing €8,320 per year in profit.
⚠️ Note:
Desserts often have a higher food cost than main courses (35-45%), because they contain more premium ingredients like chocolate, nuts, and cream.
The basic formula for portion weight
The ideal portion weight depends on your desired food cost and purchase price per kilo. The formula is:
Maximum portion weight (grams) = (Selling price excl. VAT × Food cost %) / Purchase price per kilo × 1000
💡 Example:
You sell tiramisu for €8.50 (incl. 9% VAT) and want 35% food cost:
- Selling price excl. VAT: €7.80
- Desired food cost: 35%
- Maximum ingredient costs: €2.73
- Purchase price tiramisu: €24 per kilo
Maximum portion weight: €2.73 / €24 × 1000 = 114 grams
Different dessert types and their ideal weights
Not every dessert has the same ideal weight. Here are common guidelines from tracking this across dozens of restaurants:
- Cakes and pastries: 80-120 grams
- Mousses and bavarois: 90-130 grams
- Ice cream (scoops): 50-70 grams per scoop
- Tiramisu/trifle: 100-140 grams
- Crème brûlée: 80-100 grams
- Panna cotta: 90-120 grams
💡 Example chocolate mousse:
Selling price: €7.00 incl. VAT, desired food cost: 40%
- Excl. VAT: €6.42
- Max ingredient costs: €2.57
- Mousse costs €22/kg to make
Ideal weight: €2.57 / €22 × 1000 = 117 grams
Accounting for garnish and decoration
Don't forget to include the garnish in your cost price. A sprig of mint, berry sauce, or cookie also counts toward your food cost.
- Berry sauce: 15-20 grams = €0.15-0.25
- Whipped cream: 10-15 grams = €0.08-0.12
- Chocolate shavings: 2-5 grams = €0.10-0.25
- Cookie: 1 piece = €0.15-0.35
💡 Complete panna cotta calculation:
Selling price €6.50 incl. VAT, food cost 38%:
- Panna cotta itself: 100g at €18/kg = €1.80
- Berry sauce: 20g at €12/kg = €0.24
- Mint leaves: €0.05
- Total ingredient costs: €2.09
Food cost: €2.09 / €5.96 = 35% ✓
Practical tips for consistent portions
Once you know your ideal weight, you need to ensure every portion weighs the same:
- Use a portion spoon: Measure which spoon gives you the right weight
- Check weights regularly: Verify weekly that your team is serving the correct portions
- Use molds: For mousses and bavarois, fixed molds ensure consistency
- Train your team: Let everyone know why portion sizes matter
⚠️ Note:
During a busy service, portions often increase. Train your team to use the correct amounts even under pressure.
Adjusting your portion weight
Your portion weight isn't set in stone. Adjust when:
- Ingredient prices rise: Smaller portions or higher selling price
- Guests complain about size: Too small can cost you sales
- Many desserts are left over: Portions may be too large for the price
- Food cost rises above budget: Check if portions still add up
A food cost calculator can help you quickly recalculate how different portion sizes affect your margins without manual calculations.
How do you calculate the ideal portion weight? (step by step)
Determine your desired food cost percentage
For desserts, 35-45% is standard. Choose a percentage that fits your concept and profit targets. Higher food cost can work if you need fewer staff for desserts.
Calculate your maximum ingredient costs per portion
Divide your selling price excl. VAT by 100 and multiply by your desired food cost percentage. At €7.80 excl. VAT and 35% food cost: €7.80 × 0.35 = €2.73 maximum.
Calculate the cost price per kilo of your dessert
Add up all the ingredients that go into 1 kilo of your dessert: cream, sugar, eggs, chocolate, etc. This gives you the cost price per kilo of dessert.
Calculate the maximum portion weight
Divide your maximum ingredient costs by the cost price per kilo and multiply by 1000. This gives you the maximum weight in grams per portion.
Include garnish and decoration
Subtract the costs of sauce, whipped cream, cookies, etc. from your maximum ingredient costs. The remaining amount determines the weight of your main dessert.
✨ Pro tip
Weigh your top 3 desserts for the next 2 weeks during different shifts. If portions consistently run 15-25% over target, you're likely losing €200-400 monthly just on those items.
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
Can my dessert food cost be higher than 35%?
Yes, desserts can often have a higher food cost (up to 45%) because they require less labor than main courses and guests are willing to pay more for premium ingredients.
How often should I check my portion weights?
Check at least once per month whether your team is still serving the correct portions. With new staff or after complaints about portion size, you can check more frequently.
What if guests say my desserts are too small?
Then you have two options: larger portions at higher food cost, or raise your selling price. Calculate both scenarios to see which brings in more revenue.
Should I include VAT in my portion calculation?
No, always calculate using the price excl. VAT. The VAT (9% on desserts) goes to the tax authority and doesn't count toward your margin.
Can I offer different portion sizes?
Yes, but calculate the correct selling price for each size. A 'small' and 'large' option can increase your average check value.
How do I handle seasonal price fluctuations for ingredients like berries?
Create two portion calculations - one for peak season and one for off-season pricing. Switch between them or adjust your menu seasonally to maintain margins.
What's the best way to cost multi-component desserts with different shelf lives?
Calculate each component separately, then combine. This helps you track waste more accurately and identify which elements are driving up your costs most.
⚠️ 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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