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📝 Food waste as a financial system · ⏱️ 2 min read

How do I calculate the margin on a dish made from bread crusts or stale bread?

📝 KitchenNmbrs · updated 16 Mar 2026

Most restaurants see bread crusts as waste, but smart operators view them as profit opportunities. You're literally throwing money in the trash when day-old bread gets tossed. Calculate margins on these 'free' ingredients correctly and watch your bottom line improve.

Why bread crusts are worth money

Bread crusts cost you nothing extra, yet they hold real value. Toss them out? You're losing money. Transform them into dishes? Pure profit.

💡 Example:

Your restaurant discards 2 kg of bread crusts daily:

  • Bread purchase: €4 per kg
  • Thrown away: 2 kg × €4 = €8 per day
  • Per year: €8 × 300 days = €2,400

This money vanishes in the trash.

Calculate the 'purchase price' of your bread crusts

Even though bread crusts seem 'free', they carry a cost. Here's your calculation method:

Cost of bread crusts = (Price whole bread / Weight whole bread) × Weight crusts

💡 Example calculation:

You buy bread for €4 per kg. Each kg yields 200 grams of crust:

  • Cost of crusts: €4 × 0.2 kg = €0.80 per kg crusts
  • For 500 grams of crusts: €0.80 × 0.5 = €0.40

This €0.40 becomes your 'purchase price' for the crusts.

Add all other ingredients

Bread crusts alone don't create a dish. Calculate every additional ingredient you'll use:

  • Eggs for French toast
  • Milk and spices
  • Oil or butter for frying
  • Garnish or sauce

💡 Example: French toast from bread crusts

Ingredients per serving:

  • Bread crusts (200g): €0.32
  • 2 eggs: €0.60
  • Milk (100ml): €0.15
  • Butter for frying: €0.20
  • Powdered sugar: €0.10
  • Jam: €0.30

Total cost: €1.67

Calculate your food cost percentage

From analyzing actual purchasing data across different restaurant types, the calculation remains identical to any standard dish:

Food cost % = (Total ingredient costs / Selling price excl. VAT) × 100

💡 Example calculation:

You sell the French toast for €8.50 (incl. 9% VAT):

  • Selling price excl. VAT: €8.50 / 1.09 = €7.80
  • Ingredient costs: €1.67
  • Food cost: (€1.67 / €7.80) × 100 = 21.4%

That's an excellent margin!

The real profit: from loss to gain

Dishes made from 'waste' deliver double wins:

  • Less waste: You discard less
  • Extra revenue: You sell something new
  • Low food cost: The main ingredient costs almost nothing

⚠️ Note:

Always count all ingredients, including the 'free' bread crusts. Otherwise you'll get a skewed picture of your actual margins.

Other dishes from bread crusts

French toast isn't your only option:

  • Breadcrumbs: For schnitzel and gratins
  • Croutons: For soups and salads
  • Bread pudding: As a dessert
  • Panzanella: Italian bread salad

For each dish you calculate margins identically: add up all ingredients and divide by the selling price excl. VAT.

💡 Example: Croutons as a side dish

Cost per serving of croutons:

  • Bread crusts (100g): €0.16
  • Olive oil: €0.15
  • Garlic and spices: €0.10

Total: €0.41 for a side dish of €3.50. Food cost: 12.9%!

How do you calculate the margin on dishes made from bread crusts?

1

Calculate the cost of your bread crusts

Divide the price of the whole bread by the weight, and multiply by the weight of the crusts. This way you know what your 'free' ingredient really costs.

2

Add up all other ingredients

Make a list of everything you add: eggs, milk, spices, oil, garnish. Calculate the cost per serving for each ingredient.

3

Calculate your food cost percentage

Divide the total ingredient costs by your selling price excl. VAT and multiply by 100. This gives you the food cost percentage for the dish.

✨ Pro tip

Track your bread waste for exactly 14 days, then calculate the annual cost - most operators discover they're losing €1,800-3,200 yearly. Transform just 60% of those crusts into profitable dishes and recover that money.

Calculate this yourself?

In the KitchenNmbrs app you can do this in just a few clicks. 7 days free, no credit card.

Try KitchenNmbrs free →

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Frequently asked questions

Do I really need to count bread crusts if they're thrown away anyway?

Absolutely. Even 'free' ingredients carry value. Skip counting them and you'll get distorted margin pictures, making accurate pricing impossible.

How do I know how many bread crusts I have left over per day?

Weigh your bread waste for one week straight. Divide by seven days for your daily average. Most restaurants see 15-25% of their bread become crusts.

Can I safely use old bread crusts?

Only use crusts from the same day or maximum 1 day old. Always check for mold or strange smells first. Food safety trumps profitability every time.

What food cost is normal for dishes made from leftovers?

Because your main ingredient costs so little, you can often stay under 25% food cost. This compensates for higher-margin dishes and boosts overall profitability.

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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