The purpose of this study was to design capacitors and a coil, which are components of an electric circuit, for improved performance of multi-stage electromagnetic coil guns. The electromagnetic force generated in the solenoid coil is determined by the magnitude of the current, supplied from the capacitor to the solenoid coil. Since the current flowing in the solenoid coil is not constant, the variability of electromagnetic force becomes larger. Design variables such as the capacitor capacity, coil winding, and firing distance are complicatedly related and determine the coil gun firing rate together. This study sets the number of turns of the solenoid coil, capacitor capacity, and firing distance as design variables for a five-stage coil gun. The electric circuit configuration of the coil gun with the highest velocity in each firing stage, was derived through the design of experiments. The coil gun’s finite element analysis model was constructed using ANSYS Maxwell, an electromagnetic analysis program, and implemented through a transient simulation to calculate the projectile’s velocity. Additionally, a prototype was manufactured based on the derived results to conduct launch experiments, and the experimental and simulation results were compared.