This article measures farm‐level postharvest losses for maize, soya and groundnuts among 1,200 households in Malawi. Farmers answered a detailed questionnaire designed to learn about losses during harvest and transport, processing and storage and which measures both complete losses and crop damage. The findings indicate that fewer than half of households report suffering losses conditional on growing each crop. Conditional on losses occurring, the loss averages between 5 and 12 per cent of the farmer's total harvest. Compared to nationally representative data that measure losses using a single survey question, this study documents a far greater percentage of farmers experiencing losses. We find that losses are concentrated in harvest and processing activities for groundnuts and maize; for soya, they are highest during processing. Existing interventions have primarily targeted storage activities; however, these results suggest that targeting other activities may be worthwhile.