The calculation of the one-electron finite nuclear size corrections to the energy levels of multicharged ions by the known nuclear charge distribution moments (r2> and (r4) using the effective radius method is considered. Approximative formulae which allow calculation of the one-electron nuclear size corrections at intervals Z = 1-100 (Z is the nuclear charge) with a relative error =0.2% using the known moments (r2) and (r4> are proposed.