In tokamak fusion research, expansions of the flux in solutions to the homogeneous Grad-Shafranov equation (multipolar moments method) have been shown to provide a good description of the flux outside the plasma. In practice, moments of the toroidal current distribution are more often used, because they relate directly to meaningful global plasma parameters. The letter presents a method by which exact relationships between the multipolar moments and the current moments can be obtained. Results for some important special cases are presented.