DGPV Calculator estimates Solar PV and Storage Capacity required to replace the Diesel Genset (DG) based power at a grid connected installation. It calculates the output based on Type and Load Requirement; Area available for PV; and User’s need for replacement i.e. Full or Partial. The Calculator offers the a) commercial viability in terms of returns and payback; b) tax benefits and c) energy generation from the solar PV power plant and Battery Energy Storage System (BESS). The Calculator is easy to use even for a layman.