The fins are generally used to increase the heat transfer rate from the system to the surroundings by increasing the heat transfer area. The fins are generally extended surfaces or projections of materials on the system. The fins are commonly used on small power developing machine as engines used for motorcycles as well as small capacity compressors. They are also used in many refrigeration systems (evaporators and condensers) for increasing the heat transfer rates. In the present analysis, the fins that are of different cross sections and of same material (aluminium) are considered. The knowledge of efficiency and effectiveness of the fin are necessary for proper design of fins. The main objective of our analysis is to determine the most effective cross section among the various cross sections available. The efficiency and effectiveness of various cross sections are determined experimentally by cross sectional area and volume as constant for each cross section.