One of the most important aspects of structural engineering is how well buildings perform during earthquakes. This project's research examines, taking into account a number of factors, how Irregularities affect a building's seismic reaction. Using the computer-aided tools like STAAD.Pro, a comparative analysis was conducted to understand how various irregularities affect structural behavior during earthquake. The prospective project uses response spectrum reasoning that is dynamic study among STADD PRO to study the seismic response of a multi-story G + 6 RCC building with three Irregularities that is stiffness, mass, and plan. Seismic zone IV is taken into consideration and the Medium Soil is used for these project. This study compares the effect of various Irregularities with a regular building G + 6 based on storey displacement, storey drift, and storey shear. The study examines irregularities such as plan irregularity, vertical mass irregularity and stiffness irregularity among others. The verdicts of this provisional study provide valuable observations into the seismic action of constructions under different irregular conditions by considering various parameters and by using computer aided tool like STAAD.Pro this research can be very helpful for understanding the best configuration for seismic performance of the building. By analyzing all the Results of various parameters like storey shear, displacement and drift again for one results of base shear and time period, it possibly carried out that Regular Building design can show more strength and good efficiency as oppose to Irregular Building Structure.