Portion size directly determines your food cost percentage. Many food truck entrepreneurs estimate portions, causing them to lose money unknowingly. Here's exactly how to calculate the right portion size that matches your desired profit margin.
Why portion size matters for your profit
Every gram of ingredient equals money in a food truck. Oversized portions destroy your profit, while undersized portions anger customers. You need the sweet spot between customer satisfaction and profitability.
💡 Example:
You sell a burger for €12.00 (incl. 9% VAT) and want a food cost of 30%.
- Selling price excl. VAT: €12.00 / 1.09 = €11.01
- Maximum ingredient costs: €11.01 × 0.30 = €3.30
You can use a maximum of €3.30 in ingredients per burger.
The basic formula for portion calculation
Calculate the right portion size with this formula:
Maximum ingredient costs = Selling price excl. VAT × (Desired food cost % / 100)
Then divide these costs across your ingredients based on their purchase price per kilo or unit.
Step by step: from desired food cost to portion size
💡 Practical example - Pulled pork sandwich:
Selling price: €14.00 (incl. VAT), desired food cost: 28%
- Selling price excl. VAT: €14.00 / 1.09 = €12.84
- Ingredient budget: €12.84 × 0.28 = €3.60
- Pulled pork: €18/kg = €0.018/gram
- Maximum meat: €2.00 / €0.018 = 111 grams
- Remaining budget (€1.60) for bun, sauce, lettuce
Distributing different ingredients across your budget
Not every ingredient costs the same. From tracking this across dozens of restaurants, here's how to distribute your ingredient budget wisely:
- Main ingredient (meat/fish): 50-65% of your budget
- Sides (bun, fries): 20-30% of your budget
- Garnish (lettuce, tomato): 10-15% of your budget
- Sauces and seasonings: 5-10% of your budget
⚠️ Note:
Don't forget any ingredient, including cooking oil or seasoning salt. These small amounts add up quickly.
Handling seasons and price fluctuations
Food truck ingredients vary in price due to seasons and market conditions. Check your purchase prices monthly and adjust portions accordingly.
💡 Seasonal example:
Tomatoes cost €4/kg in winter, €2/kg in summer.
- Winter: 50 grams tomato = €0.20
- Summer: 100 grams tomato = €0.20
Adjust your portion, not your price.
Control: measure your actual portions
Calculating is one thing, practice is another. Regularly measure what you actually serve:
- Weigh 10 portions of the same dish
- Calculate the average
- Compare with your calculated portion
- Train your team on consistency
Food truck specific challenges
Food trucks face unique portioning challenges:
- Limited space: No large scale, work with measuring cups
- Speed: Portions need to be quick and consistent
- Stress: Long lines cause your team to over-portion
- Visibility: Customers see you cooking, small portions stand out
⚠️ Note:
Customers see you portion in food trucks. A scoop that looks skimpy can damage your reputation, even if it's the correct amount.
Digital tools for portion control
Manual calculations take time you don't have in a busy food truck. Apps automatically calculate your maximum portion size per ingredient based on your desired food cost.
You enter your purchase prices, set your desired food cost, and immediately see how many grams of each ingredient you can use without making a loss.
How do you calculate the right portion size? (step by step)
Determine your maximum ingredient budget
Divide your selling price (excl. VAT) by your desired food cost percentage. A burger of €12.00 (excl. VAT) with 30% food cost gives you €3.60 budget for ingredients.
Distribute the budget across ingredients
Give 50-65% of your budget to the main ingredient (meat/fish), 20-30% to sides, 10-15% to garnish and 5-10% to sauces. This way you know how much you can spend per ingredient.
Calculate the grams per ingredient
Divide the budget per ingredient by the purchase price per gram. €2.00 budget for meat that costs €18/kg: €2.00 / €0.018 = 111 grams of meat per portion.
Test and measure in practice
Weigh 10 portions of the same dish and calculate the average. Train your team to maintain these portions consistently, even during busy times.
✨ Pro tip
Weigh your first 15 portions during slow Tuesday prep time, not during Friday rush. This trains muscle memory for correct amounts before stress kicks in.
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 if my calculated portion seems too small for customers?
Then raise your selling price instead of your portion. A low price with oversized portions means a loss. Customers prefer to pay a bit more for a fair portion than pay little for a skimpy one.
How often should I update my portion calculation?
Check your purchase prices monthly and adjust portions when prices change by more than 10%. With seasonal products this may need to happen more frequently.
What if my team portions inconsistently during busy times?
Use standardized measuring cups and spoons instead of 'by feel'. Train the team during quiet moments and make clear agreements about portion size.
Should I include VAT in my portion calculation?
No, always calculate with the price excluding VAT. VAT is for the tax authority, not for your ingredients. A price of €12.00 incl. VAT is €11.01 excl. VAT.
📚 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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