Irregularity in plan shape is very common and sometimes unavoidable for providing proper ventilation in and around a tall building. In this present study, the pros and cons of using irregular type butterfly plan-shaped building over regular square plan-shaped buildings are discussed. Two turbulence models, standard k-epsilon (SKE) and shear stress transport (SST), were used for the validation of the numerical model, and the data were compared with previous experimental results of Commonwealth Advisory Aeronautical Research Council (CAARC) building model from literature. The force coefficients (both X and Y direction) and external pressure coefficients are observed considering four different heights and five different irregularity ratios of the butterfly building for wind incidence angle ranging between 00 and 450 at an interval of 150. The variation of pressure along various faces of the building is analysed with the help of contours and horizontal peripheral lines. With the increase in the irregularity ratio, the overall plan area consumed by the building is increased although the ventilation of the building is improved drastically along with a decrease in the force coefficient acting on the building and the maximum local suction at the corner regions.