This study critiques available methods for the national-level, sector specific, characterisation of food waste. Such estimates are required to account for the environmental and socio-economic implications of food waste, and to identify the highest impact and most cost-effective solutions to reduce those negative outcomes associated with wasted food. Australian results are compared using three fundamentally different approaches taken from the literature, along with two variants implemented for this study. The results are extremely inconsistent, suggesting that our current quantitative knowledge on Australian food waste may not be sufficient for optimal prioritisation of mitigation options. While these ‘conventional’ methodologies may not be sufficient in isolation, their strengths are complementary and would ideally be integrated into a single analytical framework that incorporates the best available top-down and bottom-up datasets.