Use the How Much Food Do You Waste Each Week
To estimate your food waste cost, multiply your weekly grocery spend by the percentage of food you think is wasted, then multiply the weekly cost by 52 for an annual estimate.
Example: £80 weekly shop × 10% waste = £8 wasted per week
£8 × 52 = £416 wasted per year
It will only ever be an estimate, because households waste different foods in different ways. The aim is not perfect accounting — it is to spot where money is leaking from your weekly shop.
Want the answer faster?
Use the calculator to estimate weekly, monthly and yearly food waste cost from your grocery spend.
Use the food waste cost calculatorWhy food waste cost matters
Food waste can feel small because it happens in little bits: half a loaf of bread, fruit that goes soft, leftovers that sit in the fridge, or ingredients bought for one recipe and never used again.
But small weekly waste adds up. WRAP’s 2026 Food Waste Action Week release says the total cost of UK food waste is about £17 billion per year, with around £1,000 a year for an average household of four. Use those figures as broad context rather than a prediction for your own home.
The basic food waste cost formula
The simplest approach is to start with your average grocery spend and estimate how much is wasted.
Monthly waste cost = weekly waste cost × 52 ÷ 12
Yearly waste cost = weekly waste cost × 52
| Weekly grocery spend | Estimated waste | Weekly cost | Yearly cost |
|---|---|---|---|
| £60 | 5% | £3 | £156 |
| £80 | 10% | £8 | £416 |
| £120 | 15% | £18 | £936 |
What counts as food waste?
For a household estimate, food waste usually means edible food you bought but did not eat. This might include food thrown in the bin, leftovers that are not used, expired food, unused ingredients or food scraped from plates.
Common wasted foods
Bread, salad, fruit, vegetables, milk, leftovers, cooked rice, pasta, potatoes and opened packets.
Sometimes unavoidable
Peels, bones, shells and inedible parts are different from edible food that could have been eaten.
For simple money tracking, focus first on edible food. That is the part most likely to affect your grocery budget.
Worked example: weekly shop
Imagine a household spends £95 a week on groceries and thinks around 12% is wasted.
£11.40 × 52 = £592.80 wasted per year
If that household reduces waste from 12% to 7%, the estimate changes:
Difference = £11.40 - £6.65 = £4.75 saved per week
£4.75 × 52 = £247 saved per year
A more accurate method: list the food you throw away
If you want a more realistic estimate, track wasted items for one or two weeks. Write down the item, roughly how much was wasted and the estimated price.
| Item wasted | Estimated amount | Estimated cost |
|---|---|---|
| Bread | Half loaf | £0.75 |
| Bagged salad | One bag | £1.20 |
| Cooked pasta | Two portions | £1.00 |
| Fruit | Four pieces | £1.60 |
Then add the item costs together and multiply by 52 if the week was typical. This method is better than guessing a percentage if you are actively trying to cut waste.
Simple ways to reduce food waste cost
- Plan meals around what is already in the fridge, freezer and cupboards.
- Use the grocery cost calculator to spot expensive items and repeated buys.
- Scale recipes with the recipe scaler before cooking too much.
- Freeze spare portions quickly if you know they will not be eaten in time.
- Keep a short “use first” section in the fridge for items close to date.
- Check whether a recipe can use leftover vegetables, cooked meat or opened tins.
How food waste affects cost per serving
Food waste also changes your real cost per serving. If you cook six portions but only eat four, the cost per eaten portion is higher than it first looked.
Planned servings = 6 → £2 per serving
Eaten servings = 4 → real cost = £3 per eaten serving
This is why batch cooking only saves money when the extra portions are actually eaten or frozen.
Common food waste cost mistakes
Using one unusual week
A holiday week, party week or illness week can distort the estimate. Use a normal week where possible.
Counting all packaging waste
This guide is about edible food cost, not general household rubbish.
Ignoring leftovers
Leftovers are only a saving if they are eaten later. Uneaten leftovers are part of the waste cost.
Forgetting small items
Small daily waste can add up faster than one expensive item thrown away occasionally.
FAQs
How do I calculate food waste cost?
Multiply your grocery spend by the percentage of food you estimate is wasted. For example, £80 a week with 10% waste is £8 a week, or £416 a year.
What percentage should I use?
Use your own best estimate or track actual wasted items for a week. If you are unsure, try a few scenarios such as 5%, 10% and 15% to see the range.
Is food waste cost the same for every household?
No. It depends on household size, shopping frequency, meal planning, storage, freezer use, portion sizes and how often leftovers are eaten.
Should I include food scraps?
For a money-saving estimate, focus on edible food that could realistically have been eaten. Inedible parts such as bones, shells and peelings are a different issue.
Can reducing food waste save money?
Often, yes. The biggest savings usually come from buying only what will be used, eating leftovers, freezing spare portions and planning around ingredients already at home.
Is the calculator exact?
No. It is an estimate. Prices, portion sizes and waste habits vary, so the result should be used as a planning guide rather than an exact figure.
Sources and notes
This guide uses simple household budgeting maths and UK food-waste context from WRAP. WRAP’s UK Food Waste & Food Surplus Key Facts report provides national food-waste statistics, while its 2026 Food Waste Action Week release gives the £17 billion annual cost and £1,000 average household-of-four context.