Beam time at large user-program-based X-ray and neutron scattering facilities is in high demand and always at a premium.CrystalPlan, a highly efficient experiment-planning software, has been developed to maximize the use of available beam time per sample per experiment. This program can calculate and optimize the data coverage of a crystal in reciprocal space in a single-crystal diffraction time-of-flight experiment.CrystalPlancan help a user build an experiment plan that will acquire the most unique data possible, with sufficient coverage but limited redundancy, therefore increasing scientific productivity. A user-friendly graphical user interface, including a three-dimensional viewer, an automated coverage optimizer and an option to reorient the crystal for the measurement of selectedhklreflections on specific detector positions, are among its useful features. A sample use case of the program with the TOPAZ beamline at the Spallation Neutron Source will be presented.