Costs associated with research data management count as eligible costs for many research funders and must therefore be considered as early as the proposal stage. In any case, however, RDM costs should be considered as efficient use of time and money is essential for successful project completion. In cases where researchers want to claim costs associated with RDM, many funders require a cost calculation for data management along with a DMP in the project application (e.g. personnel, infrastructure, training).
The University of Utrecht and the UK Data Service offer tools for the estimation of data management costs which might be of interest.