Solar photovoltaic (PV) is now the third-most important renewable energy source in terms installed capacity, and is the fastest growing renewable energy technology adopted in the residential and commercial building sectors. The power generation of a fixed-panel solar plant depends on several parameters, some of which are considered fixed for the lifetime of the panel, and others of which vary or have a degree of stochasticity. A panel’s geographic location, tilt angle, and directional orientation are some of the factors that are considered fixed, while temperature, insolation, and snow coverage are factors that can vary depending on season and time, and have a degree of stochasticity. It is important in the solar PV system design to consider all these factors in order to maximize the system outputs and to achieve the greatest degree of economic efficiency. The research team has identified a clear need for a user-friendly, reliable computer-based solar PV system design tool that can facilitate building assessment in terms of geometrical, geographical, and meteorological parameters in order to improve the configuration of the solar PV system. The goal of this project is to develop a web-based user-friendly parametric numerical tool that can help solar PV system designers and other users to make efficient and optimal decisions for both commercial and residential buildings.