Large and complex products such as aircrafts or wind energy plants are usually produced in small batches. This leads to particular requirements for logistics with regard to process efficiency, flexibility and reliability as well as coordination and control of the processes. In practice, the consolidation of parts from different storage areas is a labour-intensive process, which must be considered in the planning or remodelling of warehouses. This work presents an analytical model to determine the consolidation time within a single formula at an early planning stage. Within this formula transport, handling, base and allowance times are considered. Finally, the analytical model is applied in an industrial project which deals with the new planning of warehouses for a large equipment manufacturer. The presented work connects academic approaches for calculating the commissioning time with practical experiences gained in industrial projects. Researchers benefit from this work, as practical considerations and corresponding solutions are pointed out and insights into practical projects are given, while logistics planners could benefit by applying the developed model.