A restaurant serving 200-gram steaks at €18.50 switched to per-gram pricing and discovered their food costs swinging from 22% to 41% depending on portion size. Fixed portions deliver predictable costs per plate, while per-gram sales create fluctuating expenses with each customer order. This variance can impact your monthly profits by hundreds of euros, particularly with premium ingredients like aged beef and fresh seafood.
The difference between fixed portions and per-gram sales
Fixed portions mean you serve identical amounts every time. Per-gram sales let customers choose their quantity. This flexibility sounds appealing, but it fundamentally changes your cost structure and margin calculations.
💡 Fixed portion example:
Steak à la carte: always 220 grams
- Beef: €28/kg = €6.16 per portion
- Side dish: €1.20
- Sauce: €0.80
Total cost price: €8.16 per plate
💡 Per-gram sales example:
Steak per 100 grams: customer decides how much
- 200g order: €5.60 meat + €2.00 side dish = €7.60
- 300g order: €8.40 meat + €2.00 side dish = €10.40
- 150g order: €4.20 meat + €2.00 side dish = €6.20
Cost price ranges from €6.20 to €10.40
The food cost calculation per system
Fixed portions maintain consistent food cost percentages. But per-gram sales create fluctuation because accompaniments and garnishes carry fixed costs regardless of protein weight.
- Fixed portion: Food cost = (Total cost price / Selling price excl. VAT) × 100
- Per-gram sales: Food cost = ((Grams × Price per gram) + Fixed costs) / Selling price excl. VAT) × 100
⚠️ Note:
Per-gram sales make smaller portions proportionally expensive due to unchanging accompaniment costs. A 100-gram steak with €2 sides carries higher food cost percentage than a 300-gram portion with identical sides.
Impact on your profit margin
Your chosen system directly influences profitability. You'll notice dramatic differences especially with costly proteins paired with inexpensive sides. This represents one of the most common blind spots in kitchen management - underestimating how portion flexibility affects your bottom line.
💡 Impact example:
Salmon sales: €45/kg, selling price €8.50 per 100g
- Fixed portion 180g: cost price €8.10, food cost 35%
- Per-gram sales 120g: cost price €5.40, food cost 27%
- Per-gram sales 250g: cost price €11.25, food cost 48%
Difference: 21 percentage points between small and large
Which system do you choose when?
Your decision depends on restaurant concept, customer preferences, and cost structure. Each approach offers distinct advantages and challenges.
- Fixed portions: Predictable cost price, simple calculation, consistent picture
- Per-gram sales: Customer flexibility, higher revenue on large portions, complex cost management
⚠️ Note:
Per-gram sales require minimum portion requirements to prevent small orders from becoming unprofitable due to fixed accompaniment expenses.
Calculation in practice
To calculate differences between systems, analyze your average per-gram portion sizes and compare them with equivalent fixed portions.
Tools like a food cost calculator help you model both scenarios and determine which system optimizes your situation. These applications automatically compute food costs across different portion sizes, revealing where your optimal profit margins exist.
How do you calculate the difference? (step by step)
Calculate cost price fixed portion
Add up all ingredients for your standard portion size. Don't forget side dishes, sauces, and oil. This is your fixed cost price per plate.
Calculate cost price per-gram sales
Divide your ingredients into: variable costs (per gram) and fixed costs (side dish, sauce). Formula: (Grams × Price per gram) + Fixed costs.
Compare food cost percentages
Calculate for both systems: Cost price / Selling price excl. VAT × 100. The difference shows which system is more profitable at different portion sizes.
✨ Pro tip
Track your per-gram sales data over 6 weeks to identify ordering patterns. If 75% of customers order within a 50-gram range, you're essentially running fixed portions with extra complexity.
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
Which system gives more profit?
That depends on your average portion size and customer ordering patterns. Per-gram sales generate higher profits on large portions but lose money on small orders due to fixed accompaniment costs.
How do I prevent losses on small portions with per-gram sales?
Establish minimum portion requirements. For instance, require minimum 150 grams for steak orders so fixed costs for sides and sauces don't disproportionately impact margins.
Can I combine both systems on the same menu?
Absolutely, and many successful restaurants use this hybrid approach. You might offer fixed portions for daily specials while using per-gram pricing for premium à la carte items. Just calculate food costs separately for each system.
How should I price accompaniments with per-gram protein sales?
Consider bundling sides into the per-gram price or charging separately for accompaniments. Some restaurants add €3-4 for potato and vegetable regardless of protein weight to maintain consistent margins.
📚 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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