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📝 Specific kitchen types & concepts · ⏱️ 2 min read

How do I calculate the cost price of a portion of fries including potatoes, oil and sauce?

📝 KitchenNmbrs · updated 16 Mar 2026

You calculate the cost price of fries by adding up all ingredients: potatoes, oil and sauce. While most restaurant owners focus solely on potato costs, they're missing nearly 40% of the actual expense. The overlooked oil absorption and sauce portions can make or break your profit margins.

All ingredients for one portion of fries

For a standard portion of fries of 200 grams you need:

  • Potatoes: 300 grams (for 200 grams of fries due to moisture loss)
  • Frying oil: approximately 10% absorption = 20 grams of oil
  • Mayonnaise: 1 sachet of 20 grams
  • Salt: 1 gram

💡 Example cost price calculation:

Standard portion of fries 200 grams:

  • Potatoes (300g): €0.18 (at €0.60/kg)
  • Frying oil (20g): €0.05 (at €2.50/kg)
  • Mayonnaise (20g): €0.12 (at €6.00/kg)
  • Salt (1g): €0.001 (at €1.00/kg)

Total cost price: €0.35 per portion

Calculate frying oil consumption correctly

The trickiest part is calculating oil consumption. Fries absorb approximately 8-12% of their weight in oil during frying. Use 10% as a rule of thumb for a good estimate.

⚠️ Note:

Don't forget to include the cost of replacing frying oil. If you replace 10 liters every 3 days and bake 500 portions of fries, that costs an extra €0.05 per portion in replacement oil.

Don't forget sauce and toppings

Many entrepreneurs only calculate potatoes and oil, but sauce can make up 25-35% of your fries cost price. Other toppings also count:

  • Mayonnaise: €0.10-0.15 per sachet
  • Ketchup: €0.08-0.12 per sachet
  • Curry/andalouse: €0.12-0.18 per sachet
  • Onions: €0.02-0.05 per portion

💡 Example with special sauce:

Fries special (mayo + ketchup + onions):

  • Basic fries: €0.23
  • Mayonnaise: €0.12
  • Ketchup: €0.10
  • Onions: €0.03

Total: €0.48 per special portion

From cost price to selling price

With a cost price of €0.35 you can calculate your selling price. For fries, a food cost of 20-25% is often used because of the low ingredient costs.

Formula: Minimum selling price = Cost price ÷ (Desired food cost% ÷ 100)

💡 Price calculation example:

Cost price €0.35, desired food cost 25%:

  • Minimum price excl. VAT: €0.35 ÷ 0.25 = €1.40
  • Price incl. 9% VAT: €1.40 × 1.09 = €1.53
  • Rounded menu price: €1.50 or €1.75

At €1.75 your food cost is: €0.35 ÷ €1.61 = 21.7%

Variations in cost price

The cost price of fries varies due to different factors. After managing kitchen operations for nearly a decade, I've seen these fluctuations dramatically impact profit margins:

  • Season: Potato price fluctuates from €0.40-0.80/kg
  • Frying oil type: Sunflower oil vs. beef fat vs. vegetable frying oil
  • Portion size: Large vs. small fries (150-250 grams)
  • Fresh vs. frozen: Fresh potatoes vs. pre-fried fries

How do you calculate the cost price of fries? (step by step)

1

Determine your portion size and ingredients

Weigh a standard portion of fries and note all ingredients: potatoes (calculate 300g for 200g of fries), frying oil, salt and sauce. Also measure how much sauce you normally give per portion.

2

Calculate the costs per ingredient

Look up the purchase prices of all ingredients and calculate what you spend per portion. For frying oil: calculate 10% absorption of the fries weight plus replacement costs.

3

Add everything up and determine your selling price

Sum all ingredient costs for your total cost price. Divide this by your desired food cost% (usually 20-25% for fries) and multiply by 1.09 for the price including VAT.

✨ Pro tip

Track your oil temperature every 4 hours during peak service - fries cooked at incorrect temperatures absorb 15-20% more oil, increasing your cost per portion by €0.03-0.04.

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

How much frying oil does fries absorb during cooking?

Fries absorb approximately 8-12% of their weight in oil. Use 10% as a rule of thumb. A portion of 200 grams therefore absorbs approximately 20 grams of frying oil.

Should I include replacement costs of frying oil?

Yes, absolutely. If you replace your frying oil every 3 days, calculate how many portions you bake in that time and divide the replacement costs across all portions.

Does the cost price differ between fresh and frozen fries?

Yes, frozen fries are often more expensive per kilo but save time and have less cutting waste. Fresh potatoes are cheaper but cost more labor and have 15-20% peeling waste.

ℹ️ This article was prepared based on official sources and professional expertise. While we strive for current and accurate information, the content may differ from the most recent regulations. Always consult the official authorities for binding standards.

📚 Sources consulted

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.

JS

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.

🏆 8 years kitchen manager at 1NUL8 Group Rotterdam
Expertise: food cost management HACCP kitchen management restaurant operations food safety compliance

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