Food waste calculator: what does your bin cost a year?
The 2025 Rabobank-KiwiHarvest survey put average household food waste at $1,364 a year and 10.9% of food bought. The calculator applies the survey rate to your weekly grocery spend. The result is an estimate based on an average, not a measurement of your waste.
What does your own spend say?
Enter your weekly grocery spend to see the estimate. The examples below show the same calculation without needing to use the form.
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How is the number calculated?
The 2025 Rabobank-KiwiHarvest Food Waste survey found the average New Zealand household reported wasting 10.9% of the food it buys each week. The calculator multiplies a weekly grocery spend by 52 weeks, then by 0.109. The national-average comparison line uses the same survey’s $1,364-a-year household figure, from Rabobank’s published findings.
What would the estimate say for a typical spend?
Each hypothetical row multiplies weekly spend by 52 weeks and the survey’s 10.9% average waste rate. Results are rounded to the nearest dollar. These are arithmetic examples, not observed results from households. Changes in spending or the waste rate change the estimate.
| Weekly grocery spend | Estimated food wasted per year (2025 survey rate) |
|---|---|
| $150 | $850 |
| $250 | $1,417 |
| $350 | $1,984 |
Source for the estimated figures: the 10.9% average waste rate in the 2025 Rabobank-KiwiHarvest survey findings.
How accurate is a self-reported rate?
The rate is self-reported, and households differ. Applying the same percentage to spending also assumes discarded food costs the same proportion as food bought. Your result could be higher or lower. Use the result to understand the scale of the published average, rather than treating it as a personal bill or a saving that an app can guarantee.
What actually lowers the number?
Build the next shop around usable food at home and the meals you expect to make. Marsonya sorts recorded stock by expiry, saves recognised dates from the camera and provides mobile reminders when notifications are allowed. Food-use reports show recorded removals, helping you notice repeat purchases that go unused. Those reports are not a complete measurement of the bin. The food waste guide explains the routine and its food-safety limits.
What else do people ask about food waste costs?
Is the estimate how much my household actually wastes?
No. The calculator applies a published average rate to the weekly spending you enter. Your own waste may be higher or lower; the result does not measure your household's discarded food.
Does a lower grocery bill prove I wasted less food?
Not by itself. Spending can change because prices, meals, household size or food already at home changed. The calculator cannot separate those causes.
Can Marsonya show food that keeps going unused?
Marsonya's food-use reports show the food recorded as consumed, expired or wasted. They can highlight repeated unused purchases, but they do not observe everything eaten or thrown away.