Following an introduction to household accounting in Germany, the paper presents the results of research projects on accounting practices in private households and reports on the subsequent development of a new household accounting system. The empirical research suggested that accounting records were kept on a regular basis in 27 per cent of German households. It was discovered that self-developed bookkeeping systems were predominantly used for that purpose. The research findings on household accounting practices were used to inform the design of Das Neue Haushaltsbuch (The New Housekeeping Book). The article charts the development of a number of variants of this prototype including a bookkeeping system which permits parallel reporting in the Deutschmark and the Euro, a system designed for use by budgeting advice services, and a pocket-money book for children.