Food Waste Calculator
Use this food waste calculator to see what the food your household throws away really costs each week, month and year, using your own prices.
Work out your food waste cost
Food you throw away (example items and values shown; replace them with your own)
For each item, enter how many times a week it goes in the bin (0.5 = every other week) and the money value of the food thrown away each time.
How the food waste calculator works
The food waste calculator multiplies the value of each throw-away by how often it happens, then adds up every item. You enter two numbers per item: how many times a week it is thrown away, and what the food thrown away each time is worth in money. Decimals are allowed, so 0.5 means every other week and 0.25 means once every four weeks.
cost per week = times per week × value each time
cost per year = cost per week × 52
cost per month = cost per year ÷ 12
A year is taken as 52 weeks and a month as one twelfth of that year, about 4.33 weeks. Each item’s share is its weekly cost divided by the weekly total, and the item with the largest weekly cost is shown as the biggest contributor. All money values are shown to two decimals; totals are worked out before rounding.
Worked example: one household’s week
These example values, in Rs, show how the food waste calculator adds up small, regular losses:
| Item | Times a week | Value each time | Per week | Per year | Share |
|---|---|---|---|---|---|
| Bread (half a loaf) | 1 | Rs 100.00 | Rs 100.00 | Rs 5,200.00 | 17.4% |
| Leftover rice and curry | 2 | Rs 150.00 | Rs 300.00 | Rs 15,600.00 | 52.2% |
| Overripe bananas | 0.5 | Rs 120.00 | Rs 60.00 | Rs 3,120.00 | 10.4% |
| Milk past its date | 0.5 | Rs 110.00 | Rs 55.00 | Rs 2,860.00 | 9.6% |
| Wilted coriander and mint | 1 | Rs 60.00 | Rs 60.00 | Rs 3,120.00 | 10.4% |
The total is Rs 575.00 a week, Rs 29,900.00 a year and Rs 2,491.67 a month (rounded). Leftover rice and curry is the biggest contributor at just over half the total. These are example values, not current prices.
How do I estimate what waste costs?
Estimate the value of the part you throw away, not the price of the whole pack. If you bin half of a Rs 200 loaf, the throw-away is worth Rs 100. For a cooked dish, use the cost of the portion left over. Our recipe cost calculator works out the cost of the amount of each ingredient you used, which is the same sum for the amount you waste. To find the price per kilogram or litre of what you buy, use the grocery unit price comparator.
For a fair count, keep a simple note on the fridge for one or two weeks and write down each thing that goes in the bin. Then enter each item in the food waste calculator with the number of times it appeared each week.
How can I waste less food?
Start with the biggest contributor, because cutting it saves the most. These habits are based on official food safety guidance:
- Chill and use leftovers on time. The USDA Food Safety and Inspection Service advises refrigerating leftovers within 2 hours and using them within 3 to 4 days. Shallow containers help them cool faster.
- Freeze what you will not eat soon. The same guidance says frozen leftovers are best within 3 to 4 months. They stay safe longer, but quality drops.
- Read the date correctly. UK guidance says a use-by date is about safety, while a best before date is about quality. Food frozen before its use-by date can be kept frozen and eaten later.
- Turn surplus into something else. Fermenting and pickling extra vegetables is one traditional way to keep them; see our guide to foods that are fermented.
- Buy and cook to plan. Our 7-day meal plan shows one way to plan a week of meals before you shop.
How much food do households waste?
Worldwide, households produce most of the world’s food waste. The UN Environment Programme’s Food Waste Index Report 2024 estimated 1.05 billion tonnes of food waste in 2022, including inedible parts, or 132 kg per person. That is almost one-fifth of the food available to consumers, and 60 per cent of it happened at household level. National averages cannot tell you what your own kitchen wastes, which is why the food waste calculator uses your own items.
What the calculator does not tell you
- Inedible parts. Peels, bones and shells you would never eat are not avoidable waste. Leave them out, or count only the edible part you threw away.
- Price changes. The result is only as good as the values you enter. Update them when prices change.
- Other costs. Cooking fuel, time and transport spent on food that is later thrown away are not included.
Sources used on this page
- UNEP: Food Waste Index Report 2024 press release (27 March 2024)
- USDA Food Safety and Inspection Service: Leftovers and Food Safety
- GOV.UK: Best before and use-by dates
Track your waste for a couple of weeks, enter it in the food waste calculator, and tackle the biggest item first.
Frequently Asked Questions
Multiply what each throw-away is worth by how many times a week it happens, then add up every item for a weekly total. Multiply by 52 for a year and divide the year by 12 for a month. Leftover rice and curry worth Rs 150, thrown away twice a week, costs Rs 300 a week, Rs 15,600 a year and Rs 1,300 a month.
It means every other week: half a time each week, or 26 times a year. Use 0.25 for once every four weeks. For something you throw away about 12 times a year, the exact weekly rate is 12 ÷ 52, about 0.23. Decimals let the calculator handle items you waste now and then, not only every week.
A year has 52 weeks but only 12 months, so the average month is 52 ÷ 12, or about 4.33 weeks. Using four weeks would make the monthly cost about 8% too low. This calculator takes a year as 52 weeks and a month as one twelfth of that year. A calendar year is a day or two longer, so the yearly figure is very slightly low.
UNEP’s Food Waste Index Report 2024 estimated that 1.05 billion tonnes of food waste were generated in 2022, including inedible parts such as peels and bones. That is 132 kg per person and almost one-fifth of the food available to consumers. Households were responsible for 60 per cent of it. Your own figure depends on your shopping, cooking and storage habits.
It depends on the kind of date. UK government guidance says a use-by date tells you when food is no longer safe to eat, so do not eat it after that date unless you cooked or froze it before then. A best before date is about quality: the food is usually safe afterwards but may not be at its best. Check it looks and smells right.