The economy of a multi-story building depends on the spacing of columns which in turn depends on panel size of slab .This study was carried out to find the effect of bay width on various design parameters like bending moment and shear force of beams and columns, also design load and design axial moment of columns, to find the optimum spacing which leads to the most economical building keeping plot area of 30 m x 30 m (constant ) having 6-stories. The entire modelling and analysis was carried out using the finite element method using the STAAD pro tool and was designed as per are IS 456:2000. The four models having different bay widths (7.5 m, 6 m, 5 m, 4.285 m). These models were subjected to general loadings such as live load corresponding to IS 875 parts 1 and 2 respectively; also earthquake loads corresponding to I.S. 1893:2002. The finding was to investigate the behaviour of column and beam as per design load, design axial moment of each story of each model, variation was studied within different model alsocurvesaredrawnfordesignload,axialmoment,bendingmoment, theshearforce of beams and columns of each story. The result show all variations of design loads and parameters. However, to reduce the complexity with the increase in population and construction requirement to accommodate more people per unit of land and decrease the cost per unit area of the structure, this research study selected work optimum size and spacing of structural components.