Many restaurant owners think they've nailed their food costs, only to discover their kitchen serves completely different portions than what's on paper. If your chef plates 250 grams of steak while your calculations assume 200 grams, you're bleeding money every single service. Here's how to bridge that gap between theory and reality.
Why portion size differences eat into your profit
Your cost calculations look perfect on paper. 200 grams of steak at €32 per kilo equals €6.40 per portion. Food cost percentage? Spot on. Margin? Looking good. But your chef consistently plates 250 grams, which means you're giving away 25% more product while charging the same price.
? Example:
Steak on your menu for €28.00 incl. 9% VAT (€25.69 excl. VAT):
- Calculated: 200g at €32/kg = €6.40 ingredient costs
- Actual: 250g at €32/kg = €8.00 ingredient costs
- Difference: €1.60 per portion
At 50 portions per week: €4,160 less profit per year
Measure your actual portion sizes
You can't fix what you don't measure. Spend one full week weighing portions of your bestselling dishes throughout each service. This isn't about micromanaging your chef - it's about understanding reality versus your calculations.
- Weigh at least 10 portions spread across different service times
- Track differences between slow Tuesday nights and packed Saturday evenings
- Don't forget side dishes, garnishes, and sauces
- Document every component that touches the plate
⚠️ Note:
That extra pat of butter, generous scoop of vegetables, or heavy-handed sauce pour all add up. Based on real restaurant P&L data, these "small" additions often account for 3-5% food cost variance.
Calculate the cost difference
Once you've captured actual serving sizes, crunch the numbers using this straightforward formula:
Extra costs = (Actual portion - Calculated portion) × Price per unit
? Pasta example:
Pasta carbonara - calculated at 120g pasta, actual 150g:
- Difference: 150g - 120g = 30g extra
- Pasta price: €3.20 per kilo = €0.0032 per gram
- Extra costs: 30g × €0.0032 = €0.096 per portion
At 80 portions per week: €400 per year in extra pasta
Adjust your cost price calculation
Now you're working with real numbers instead of wishful thinking. You've got two paths forward: tighten portion control or recalculate your pricing based on actual servings.
- Option 1: Implement strict portion control training for kitchen staff
- Option 2: Recalculate costs using actual portions and adjust menu prices
- Option 3: Hybrid approach - control high-cost items, accept variance on low-cost sides
? Adjustment example:
Steak - from 200g to 250g actual portion:
- Old cost price: €6.40 (200g × €32/kg)
- New cost price: €8.00 (250g × €32/kg)
- Food cost rises from 24.9% to 31.1%
Action: Raise price to €30.50 to keep food cost at 28%
Monitor portion size differences structurally
Portion creep happens gradually, then suddenly. New cooks arrive. Rush periods get chaotic. Generosity becomes habit. Build systematic checks into your operational rhythm.
- Monthly spot checks on your top 8 revenue-generating dishes
- Immediate monitoring after onboarding new kitchen staff
- Extra vigilance during peak service hours - portions inflate under pressure
- Invest in portioning tools: scales, spoons, ladles with clear measurements
How do you account for portion size differences? (step by step)
Measure actual portion sizes
Spend a week weighing at least 10 portions of each popular dish. Do this at different times and write down everything that goes on the plate, including side dishes and sauces.
Calculate the cost difference
Subtract your calculated portion from the actual portion and multiply by the price per unit. This gives you the extra costs per portion that you're currently missing in your food cost.
Adjust cost price or portion
Choose whether to train your kitchen to serve smaller portions, or adjust your cost price calculation with the actual portions. Then recalculate your selling prices to achieve your desired food cost.
✨ Pro tip
Weigh portions during your busiest 2-hour dinner rush every 6 weeks. Kitchen staff unconsciously become more generous with portions under pressure, which can silently inflate your food costs by 4-7%.
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Frequently asked questions
How often should I check portion sizes?
Should I also weigh side dishes and sauces?
What if my chef deliberately serves larger portions?
How do I prevent portions from gradually increasing again?
Can I estimate portion differences instead of weighing everything?
What's the biggest portion control mistake restaurants make?
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
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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