Jet projectile charge (JPC) is a relatively new type of perforating jet mainly used for defeating concrete targets. Velocity profile is an important parameter to investigate the penetration and performance of JPC. Since limited information such as X-ray radiographs and penetration depth can be obtained through the JPC experiment, the numerical simulation and further methodology are needed to depict the mechanism of JPC. This paper describes a mathematical approach based on Matlab to determine JPC velocity profile at various stand offs using three sets of jet data from numerical simulations. X-ray radiographs experimental results have been obtained at two time instants for two selected JPC design to verify the numerical accuracy. The velocity profiles by mathematical approach and simulation show good accordance. The number of experiments can be reduced by numerical simulation and analysis of velocity profiles. This approach can be generalized to any such system where explosive-metal interaction results in formation of jets.