Think of gross and net portion weight like an iceberg — what you see on the surface isn't the whole story. Most restaurant owners calculate with the weight they purchase, but that's only part of what ends up on the plate. This miscalculation can silently drain thousands from your bottom line each year.
What is gross portion weight?
Gross portion weight is the weight of an ingredient as you buy it, including all non-edible parts. Think of:
- Fish with head, bones and skin
- Meat with bone and excess fat
- Vegetables with skin and stem
- Fruit with pit and skin
💡 Example:
You buy whole salmon of 2 kg for €36.00 (€18/kg).
- Gross weight: 2,000 grams
- Gross price: €18.00 per kg
What is net portion weight?
Net portion weight represents what you actually serve after all processing. It's the clean, edible weight without any waste.
💡 Example (continued):
After filleting the 2 kg salmon, you're left with:
- Net weight: 1,100 grams fillet
- Waste: 900 grams (head, bones, skin)
- Yield: 55%
Actual fillet price: €36.00 ÷ 1.1 kg = €32.73/kg
Why this difference matters
If you calculate with gross weight, you'll dramatically underestimate your cost price. In the salmon example above:
- Wrong: calculating with €18/kg → 200g portion costs €3.60
- Correct: calculating with €32.73/kg → 200g portion costs €6.55
Difference per portion: €2.95. With 50 portions per week you lose €7,670 per year by calculating incorrectly. This represents one of the most common blind spots in kitchen management — operators think they're profitable while money leaks through improper costing.
⚠️ Note:
ALWAYS calculate with net weight for your cost price calculation. Otherwise you'll lose money without knowing it.
Typical yield per product
To help you estimate what's realistic:
- Fish (whole → fillet): 45-60% yield
- Beef (whole → portions): 75-85% yield
- Chicken (whole → fillet): 65-75% yield
- Shrimp (unpeeled): 50-65% yield
- Potatoes (peeled): 80-90% yield
💡 Example calculation:
Whole chicken €12/kg, 70% yield for fillet:
- Actual fillet price: €12 ÷ 0.70 = €17.14/kg
- 180g fillet portion: €17.14 × 0.18 = €3.09
How to measure your own yield
Do this several times for each product you use frequently:
- Weigh the product as you buy it (gross)
- Prepare it as you normally do
- Weigh the end result (net)
- Calculate: (net ÷ gross) × 100 = yield %
With tools like KitchenNmbrs you can record this yield per ingredient, so your cost prices are calculated correctly automatically.
How do you calculate net portion weight? (step by step)
Measure the gross weight
Weigh your ingredient as you buy it, before any processing. Note this weight and the purchase price per kg.
Prepare and weigh again
Process the ingredient as you normally do (fillet, peel, debone). Weigh the end result that you actually use in your dish.
Calculate actual cost price
Divide the total purchase costs by the net weight. This gives you the actual price per kg of your usable ingredient.
✨ Pro tip
Test your yield on the 3 most expensive proteins you use over the next 2 weeks. That's where incorrect calculations hit your margins hardest.
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
What do I do with waste from expensive products?
Fish and meat waste can often be used for stock or sold to a waste processor. Deduct this revenue from your purchase price to get your true ingredient cost.
Does yield differ per supplier?
Yes, product quality and size varies significantly. Therefore measure again with each new supplier, especially for expensive ingredients like fish and meat.
What about pre-prepared products?
With pre-processed products (like fillets) gross equals net weight. You pay more per kg, but have no waste and loss.
Should I also account for cooking loss?
Yes, meat and fish lose 15-25% weight during cooking due to moisture loss. Factor this into your final portion weight for accurate costing.
⚠️ EU Regulation 1169/2011 — Allergen Information — https://eur-lex.europa.eu/eli/reg/2011/1169/oj
The allergen information on this page is based on EU Regulation 1169/2011. Recipes and ingredients may vary by supplier. Always verify current allergen information with your supplier and communicate this correctly to your guests. KitchenNmbrs is not liable for allergic reactions.
In the UK, the FSA enforces allergen regulations under the Food Information Regulations 2014.
📚 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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