This research investigates the influence of fin geometry on thermal performance, focusing on solid fins with circular, ellipse, and rectangular shapes. The study calculates critical parameters such as fin efficiency, fin effectiveness, and temperature at five specific points along each fin. Theoretical models were developed to predict the heat transfer characteristics of these geometries, and these predictions were validated through thermal analysis using ANSYS software. The results reveal that fin shape plays a crucial role in determining heat dissipation efficiency, with each geometry providing distinct advantages depending on the thermal conditions. Circular fins, for instance, may offer superior performance in one scenario, while elliptical or rectangular fins excel in others. The close agreement between the theoretical models and the ANSYS simulations underscores the robustness and accuracy of the developed models. These findings provide valuable insights into optimizing fin design for enhanced thermal management in various practical applications, contributing to more efficient and effective heat dissipation solutions.