Electromagnetic forming (EMF) is a high strain rate forming technology which can effectively deform and shape high electrically conductive materials at room temperature. A field shaper is frequently used for concentrating the magnetic pressure in the desired forming area. The geometric parameters of a field shaper, as an intermediate device, affect the magnetic pressure and radial displacement in electromagnetic inside bead forming. EMF consists of electromagnetic and mechanical parts simulated using maxwell and abaqus software, respectively. The effects of geometric parameters of the stepped field shaper on magnetic pressure and radial displacement were investigated, and the best parameters were determined. Experimental tests were performed at various discharge voltages and the results were compared with simulation. The results indicated that using the stepped field shaper, the magnetic pressure concentration ratio increased from about 23–85% in comparison with using a direct coil. The maximum magnetic pressure increased by approximately 21% due to the effective concentration of magnetic pressure. Consequently, regardless of the electromagnetic energy losses because of using a field shaper, the radial displacement increased by 8% in simulation and 6% in experiment. The result of this study would be also helpful in designing field shapers in similar applications which is highly crucial and strongly recommended.