The present paper brings about changes in the conventional rectangular geometry to achieve improved performance with the least material consumption. The present work comprises four different possible cases of fin configuration for thermal performance analysis under natural convection. The first type refers to the traditional rectangular geometry, the second type is the combined rectangular–trapezoidal (same percentage) of fin geometry with reduced mass in comparison to the continuous one (Type-1), the third type and fourth type contain the combined rectangular-trapezoidal (different percentage) of fin geometry with the same mass as that of reference (Kim DK, Int J Heat Mass Transf 55, 752–761, 2012). CFD simulation for four unlike fin geometry types has been performed under natural convection surroundings to assess the performance. The performance evaluation of all the types has been made by maintaining the temperature difference between the base plate and the surrounding to vary between 10 and 50 °C. The results obtained reveal that there is a saving of 37.5% of mass from the fin geometry under Type-2, with a heat transfer improvement of 9.106% when compared to a continuous one (Type-1). The fin geometry under Type-3 and Type-4 bear the same mass, but there is a saving of 25% of mass when compared to continuous one (Type-1) and achieves a heat transfer improvement of 33.75% and 25.12%, respectively compared to the continuous one.