Food waste calculator: what does your bin cost a year?
An average New Zealand household throws away $1,364 of food a year, according to the 2025 Rabobank–KiwiHarvest survey reported by Love Food Hate Waste NZ. The same survey put the waste rate at 10.9% of food bought. Enter a weekly grocery spend below to turn that rate into a personal estimate.
What does your own spend say?
The calculator on this page runs on two published numbers and one input — nothing else, and the workings are shown below in full.
How is the number calculated?
One published rate drives the estimate: the 2025 Rabobank–KiwiHarvest Food Waste survey (run by Kantar, 1,501 respondents) found the average New Zealand household wastes 10.9% of the food it buys each week. The calculator multiplies a weekly grocery spend by 52 weeks, then by 0.109 — no other inputs, no hidden weighting. The national-average comparison line uses the same survey’s $1,364-a-year household figure, as reported by Love Food Hate Waste NZ.
What would the estimate say for a typical spend?
Three worked examples show the arithmetic before any typing happens, and they stand in for the calculator whenever JavaScript is off. Each row multiplies a weekly spend by 52 weeks and by the survey’s 10.9% waste rate. Reading them another way: at an average waste rate, roughly one grocery trolley in every nine goes to the bin — the estimate simply prices that trolley for a specific budget.
| Weekly grocery spend | Estimated food wasted per year (2025 survey rate) |
|---|---|
| $150 | $850 |
| $250 | $1,417 |
| $350 | $1,984 |
Every figure above is weekly spend × 52 weeks × the 10.9% average waste rate from the 2025 Rabobank–KiwiHarvest survey, reported by Love Food Hate Waste NZ, rounded to the nearest dollar.
How accurate is a self-reported rate?
Honestly: the rate is self-reported, and averages hide spread. The same survey found younger households reporting well above the mean and older households well below, so a personal figure could land far from the estimate in either direction. Treat the output as a mirror for the habit, not a measurement of the bin — the exact dollar answer would need weighing actual waste for a month.
What actually lowers the number?
Most household waste starts as forgetting, so the durable fixes are visibility habits: shop against a list built from the pantry, keep use-by items where eyes land, and get a nudge before dates arrive. The full playbook lives in the guide to reducing food waste at home — and Marsonya automates the remembering half with expiry scanning, reminders and a waste-rate report.