The Comparative Panel File (CPF) harmonises the world’s largest and longest-running household panel surveys from seven countries: Australia (HILDA), Germany (SOEP), Great Britain (BHPS and UKHLS), South Korea (KLIPS), Russia (RLMS), Switzerland (SHP), and the United States (PSID). The project aims to support the social science community in the analysis of comparative life course data. The CPF is not a data product but an open-source code that integrates individual and household panel data from all seven surveys into a harmonised three-level data structure. In this manual, we present the design and content of the CPF, explain the logic of the project, workflow and technical details. We also describe the CPF’s open-science platform.