Reducing food waste: how to work out yield percentage

21 October 2026 · 2 min read

Every bit of food you throw away is money you paid for and never sold. For a small café or food truck, getting on top of waste is one of the most direct ways to protect your margins. It starts with knowing your yield.

What is yield %?

Yield is how much usable food you get from what you buy.

Yield % = usable weight ÷ bought weight × 100

Peel and top 1 kg of carrots and you might be left with 850 g. That is an 85% yield, or 15% waste.

Why yield changes your costs

If carrots cost £1.00 per kg as bought, the usable carrot actually costs:

£1.00 ÷ 0.85 = £1.18 per kg

If you cost recipes using the bought price, every dish looks cheaper than it really is. In SaucySums and the free Dish Profit Calculator, the "Waste %" box on each ingredient does this sum for you.

How to measure your own yields

1. Weigh the item as it arrives.
2. Prep it the way you normally would: peel, trim, bone, cook if relevant.
3. Weigh what you can actually use.
4. Divide, and write the figure down.

Do it a few times for your main ingredients, as yields vary with the batch, season and who is prepping. Meat often loses weight in cooking too, so if you cost by cooked portion, measure the cooked yield.

Practical ways to cut waste

• Track what you bin. A simple sheet by the bin for a week, noting what and why (spoiled, over-prepped, plate waste), shows where to start.
• Prep to forecast, not habit. Look at what you sold on the same day last week before deciding how much to prep.
• Rotate stock. First in, first out keeps older stock moving. Our batch prep and stock rotation guide covers FIFO and labelling.
• Use trim well, and safely. Veg trim can go into stocks and soups, and stale bread into croutons or crumbs, as long as it has been stored and handled safely.
• Check portion sizes. Over-portioning is waste that leaves on the plate. Standard scoops, ladles and scales help everyone serve the same amount.
• Review the menu. Dishes that rarely sell but need dedicated stock are often the biggest source of waste.
• Order little and often for short-life items if your suppliers allow it.

Keep food safety first

Using up food must never mean using food past its use-by date or food that has not been kept at the right temperature. The government's guidance on understanding food labelling explains the difference between use-by and best before, and the FSA's Safer Food, Better Business pack covers stock control and chilling.

Small changes add up. Measure a few yields this week, put them into your costings, and you will know your real food cost for the first time.

© 2026 SaucySums. All rights reserved. Please do not copy this article without permission.