A restaurant buying whole salmon at €18/kg discovers they're actually paying €32.73/kg for usable fillet after trim loss. If you don't know how much product remains after processing, you're using wrong purchase prices and losing money on every portion. Here's how to calculate trim loss and determine your real cost price.
What is trim loss and why is it important?
Trim loss represents the difference between what you purchase and what you actually use. Fish requires removing heads, bones and skin. Meat needs trimming of fat and sinews. Vegetables need peeling and removal of damaged pieces.
The issue: many operators calculate based on purchase price per kilo, but use less product than they bought. This makes your actual cost price higher than you think.
💡 Example:
You buy whole salmon for €18 per kilo. After filleting you have:
- Purchase weight: 2.0 kg
- Usable fillet: 1.1 kg
- Waste (head, bones, skin): 0.9 kg
So you're not paying €18 per kilo of fillet, but €32.73 per kilo!
The formula for trim loss percentage
You calculate the trim loss percentage like this:
Trim loss % = ((Purchase weight - Usable weight) / Purchase weight) × 100
💡 Salmon example:
- Purchase weight: 2.0 kg
- Usable weight: 1.1 kg
- Trim loss: ((2.0 - 1.1) / 2.0) × 100 = 45%
Calculating actual cost price
Now it becomes crucial: your actual cost price per kilo of usable product exceeds your purchase price. The formula:
Actual cost price = Purchase price per kg / (Yield % / 100)
Where: Yield % = 100% - Trim loss %
⚠️ Watch out:
Many operators make an error here. They multiply the purchase price by the yield (€18 × 0.55 = €9.90). That's incorrect! You have LESS product, so it becomes MORE EXPENSIVE. You need to divide by the yield.
💡 Salmon example (correct):
- Purchase price: €18.00 per kg
- Trim loss: 45%
- Yield: 55%
- Actual cost price: €18.00 / 0.55 = €32.73 per kg fillet
Trim loss percentages per product group
Here are typical trim loss percentages as guidelines:
Fish
- Whole round fish → fillet: 40-55%
- Rainbow trout, salmon: 45-50%
- Cod, whiting: 50-55%
- Sole, plaice: 35-45%
Meat
- Beef (whole cuts → portions): 15-25%
- Pork (whole cuts): 10-20%
- Lamb (whole leg): 20-30%
- Chicken (whole → fillet): 35-40%
Vegetables
- Potatoes (peeling): 15-20%
- Carrots (peeling, tops): 10-15%
- Onions (peeling): 8-12%
- Lettuce (outer leaves): 10-20%
- Mushrooms (stem, cleaning): 5-10%
⚠️ Watch out:
These are guidelines, not fixed rules. Trim loss depends on your supplier's quality, season and your processing skills. Measure it yourself for your most important ingredients.
Impact on your cost price and profit
The difference between calculating with and without trim loss can be substantial. From tracking this across dozens of restaurants, the financial impact often surprises operators. Look at this example:
💡 Impact example:
Steak at €24/kg, 200g portion, trim loss 20%:
- Calculated wrong: 200g × €24 = €4.80 per portion
- Calculated correctly: 200g × €30 = €6.00 per portion
- Difference: €1.20 per portion
At 50 steaks per week = €3,120 per year difference!
Measuring trim loss in practice
For your most important ingredients, measure the trim loss yourself:
- Weigh the product upon delivery
- Process it using your standard method
- Weigh the usable end result
- Calculate the difference
- Repeat this 3-5 times and take the average
Update your cost price calculations with the actual percentages, not the guidelines from this article.
How do you calculate trim loss? (step by step)
Measure purchase weight and usable weight
Weigh your product upon arrival and after processing. Record both weights accurately. Do this for your 5 most important ingredients first.
Calculate the trim loss percentage
Use the formula: ((Purchase weight - Usable weight) / Purchase weight) × 100. This gives you the percentage you throw away.
Calculate your actual cost price per kilo
Divide your purchase price by the yield percentage (100% minus trim loss). This is what you actually pay per kilo of usable product.
Update your cost price calculation
Use the actual cost price in your recipes and food cost calculations. Check whether your menu price still matches the real costs.
✨ Pro tip
Test your trim loss on whole salmon and beef tenderloin during your next 3 deliveries. These high-cost proteins show the biggest financial impact when your percentages are off.
Calculate this yourself?
In the KitchenNmbrs app you can do this in just a few clicks. 7 days free, no credit card.
Was this article helpful?
Frequently asked questions
Do I need to include trim loss in my VAT calculation?
No, you calculate VAT on your selling price. Trim loss affects your cost price and therefore your margin, but not your VAT obligation.
What if my supplier already delivers filleted fish?
Then you have no trim loss anymore, but you pay a higher price per kilo. Compare the actual cost price: whole fish + trim loss vs. filleted fish directly.
How often should I measure trim loss again?
Measure it 3-5 times to get an average, then 1-2 times per year. Trim loss can vary due to season, supplier or product quality.
Can I sell or reuse waste?
Fish bones and vegetable scraps can sometimes be used for stock. Then deduct the value of your stock against your trim loss. Pure waste you can't sell.
What if my trim loss is higher than the guidelines?
First check your technique and tools. Dull knives and poor technique increase trim loss. If it stays structurally high, consider a different supplier.
Should I calculate trim loss differently for expensive vs. cheap ingredients?
Use the same calculation method for all ingredients. However, prioritize measuring expensive items first since errors there cost you more money.
⚠️ 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.
Calculate it yourself with KitchenNmbrs
All the formulas you learn here — KitchenNmbrs calculates them automatically. Enter your ingredients and instantly see your food cost, margin, and selling price. Try it free for 14 days.
Start free trial →