This paper aims to develop and validate an empirical model to quantify the impact of partial shading on photovoltaic (PV) panel performance. Partial shading, a significant challenge in solar power generation, can drastically reduce energy output, yet predicting its effects remains difficult using conventional models. This study introduces a methodology that models partial shading as an equivalent reduction in solar insolation across the entire panel. The model was derived from empirical data gathered under various shading scenarios, and curve-fitting techniques were employed to establish an empirical relationship between shading patterns and power loss. The proposed model was experimentally validated on a rooftop PV system in Bengaluru, India, and demonstrated precise predictions of power loss under different partial shading conditions. The framework presented can be adapted to accommodate location-specific variables, providing a versatile tool for evaluating and optimizing PV system performance in partially shaded urban environments.