Run your own numbers.

Three questions. Everything else comes from Australia’s own food-waste research, including the uncomfortable finding that the more you spend, the bigger the share you bin. Every figure is sourced at the bottom.

The calculator asks three things: how often you shop, how many people you feed, and what you spend on groceries. Everything after that comes from published research.

Where these numbers come from

Reported share of groceries wasted (9–17%). Rabobank’s Financial Health Barometer: Australian households say they bin around 11.1% of the food they buy, rising to almost 17% for households spending over $300 a week. We interpolate between those published points and hold the rate flat beyond them rather than extrapolating. rabobank.com.au
Correction for under-reporting (×2.28, capped at 30%). Those Rabobank figures are self-reported, and the Fight Food Waste CRC’s headline finding is that households bin more than twice what they think they do. This factor puts a typical household back on the measured national baseline. End Food Waste Australia
Household-size adjustment (×0.85–×1.12). A directional tilt, not a published coefficient. WRAP’s research finds smaller households waste a larger share of what they buy, because pack sizes do not scale down. Weighted across the ABS household-size distribution these average about 1.0. wrap.ngo
Dollars to kilos ($9.43/kg). Australia’s national baseline puts household food waste at 265kg and $2,500 per household per year, or 2.46 million tonnes nationally — almost a third of all Australian food waste.