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📝 Why things go wrong · ⏱️ 3 min read

Why you think a fixed margin of thirty percent is enough while your costs are rising?

📝 KitchenNmbrs · updated 16 Mar 2026

A fixed margin of 30% seems safe, but if your purchase prices rise and you don't adjust your selling prices, your profit quietly evaporates. Many restaurant owners think they've got their margins under control, while they're actually losing money every month. A fixed margin creates a false sense of security that slowly drains your profits.

Why a fixed margin is misleading

You once calculated that 30% food cost works out well. Your menu's set, your prices too. Problem solved, you'd think.

But your suppliers think differently. They raise their prices every 3-6 months. Energy gets more expensive. Transport costs more. And you? You keep your menu the same.

⚠️ Watch out:

Suppliers raise prices on average 2-4 times per year. If you only update your menu once a year, you're always playing catch-up.

What really happens to your margins

Say you started with a food cost of 30%. Your steak cost €8.00 in ingredients and you sold it for €32.00 (€29.36 excl. VAT).

💡 Example - Starting situation:

200 gram steak in January 2024:

  • Meat: €6.20 (€31/kg)
  • Sides: €1.80
  • Total ingredients: €8.00
  • Selling price: €32.00 incl. VAT (€29.36 excl.)

Food cost: 27.2% - great margin!

But then prices rise. Beef goes from €31 to €36 per kilo. Vegetables become 20% more expensive. You don't update your menu.

💡 Example - After price increases:

Same steak in October 2024:

  • Meat: €7.20 (€36/kg)
  • Sides: €2.16 (+20%)
  • Total ingredients: €9.36
  • Selling price: €32.00 (still the same)

Food cost: 31.9% - you lose €1.36 per dish!

The silent profit evaporation

That €1.36 per steak seems small. But add it up:

  • 50 steaks per week = €68 less profit
  • Per month: €272 less
  • Per year: €3,536 less profit on one dish

And this applies to every dish whose ingredients have become more expensive. At an average restaurant with 20 dishes on the menu, this can cost you €15,000 to €25,000 per year.

⚠️ Watch out:

You don't see this loss directly in your cash register. Your revenue stays the same, but your profit evaporates quietly. Only at the end of the year do you notice there's much less left than expected.

Why entrepreneurs don't notice this

There are three reasons why this problem stays invisible:

1. You focus on revenue, not margin
Your business is doing well. Full every night. Revenue figures look great. But nobody checks if the profit margin per dish still adds up.

2. Prices rise gradually
It's not one big jump from €8 to €12. It's small steps: €8.00 → €8.40 → €8.75 → €9.20. Each step seems harmless.

3. You have no real-time insight
Most entrepreneurs calculate their food cost 1 or 2 times a year. In Excel. With prices that are already months old. By then the damage is done.

💡 Example - Creeping price increases:

Salmon fillet per kilo in 2024:

  • January: €28.00
  • March: €29.50
  • June: €31.20
  • September: €33.40

Per 180 gram portion: from €5.04 to €6.01. Difference: almost €1 per plate, but you didn't notice because it happened gradually.

The solution: dynamic margin control

Instead of sticking to a fixed 30% margin, you need to control your margins dynamically:

Monthly check
Check every month your 5 top-selling dishes. Does the food cost still add up? Or has it quietly crept up?

Set price alerts
Track your suppliers' price increases from analyzing actual purchasing data across different restaurant types. Adjust your own prices immediately, or choose different ingredients.

Flexible menu
Create seasonal menus or use daily specials. Then you can respond faster to price changes without rewriting your entire menu.

A system like food cost calculators automatically warns you if your food cost exceeds your limit. That way you see immediately which dishes become too expensive, before you lose money on them for months.

How do you check if your margins still add up? (step by step)

1

Check your current purchase prices

Find out what you're actually paying now for your main ingredients. Look at your latest invoices, not old notes. Many prices have quietly risen without you noticing.

2

Calculate your actual food cost per dish

Add up all ingredients from your 5 best-selling dishes. Divide by your selling price excl. VAT and multiply by 100. If you're above 35%, you're losing money.

3

Adjust prices or change recipes

With high food cost you have two options: raise your selling price or change the recipe (smaller portions, cheaper ingredients). Choose what fits best with your concept.

✨ Pro tip

Track your weekly ingredient costs for your top 3 dishes over the next 6 weeks. You'll spot price creep before it destroys your 30% margin target.

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

How often should I check my food cost?

Check your 5 top-selling dishes monthly and your entire menu quarterly. Suppliers raise prices 2-4 times per year, so checking more often prevents surprises.

What if my guests won't accept a price increase?

Then you need to adjust your recipe: smaller portions, cheaper ingredients or different preparation method. Selling a dish at a loss isn't an option for a healthy business.

How do I prevent suppliers from surprising me with price increases?

Ask your supplier to announce price changes in advance. Many suppliers send a new price list every quarter. Put this in your calendar to check immediately.

Can't I just make my entire menu 10% more expensive?

That's a lazy solution that scares off your guests. Better to look at each dish individually. Some dishes might not need any adjustment at all.

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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