Minimum length of the supersonic nozzle has been calculated for the optimum Mach number at the nozzle exit with uniform flow at both converging and diverging section of the nozzle. The calculation has been carried out based on the method of characteristics. Numerical solution is established for the two-dimensional, steady, in viscid, irrotational and supersonic flow. It is rational to assume the flow holds the consistency in the converging section and, thereby, an arbitrary shape is assumed for the converging section of the converging-diverging nozzle. The design considerations are concentrated at the diverging section.