Green Engineering Tools Solar Calculator

This calculator is designed to help homeowners, students, technicians, consultants and businesses turn an appliance/load list into an understandable solar planning estimate. It is free to use and does not require an account.

The tool separates running power, daily energy, starting surge, PV array sizing, inverter capacity, battery backup and roof area. Major assumptions are visible and editable so users can see why a result changes instead of receiving an unexplained “exact” system size.

The software and content are maintained by Engr. Arsalan Khan, a software and web developer. The methodology page documents the formulas, defaults and limitations used by the calculator. Final electrical and structural design should be completed or checked by appropriately qualified local professionals.