A computer program is described, which permits rapid calculations of paraxial electron trajectories in multielement electrostatic cylinder lens systems. The method uses a ’’unified’’ data set for the electric potential of tube lenses with arbitrary voltage ratios, rather than solving Laplace’s equation numerically, thereby shortening the program coding drastically. With this program computer optimizations of long lens systems with respect to beam divergence and beam diameter can also be performed. Examples are given of the design of a multi‐element zoom lens and of the calculation of electron trajectories in 250 V acceleration tube with 36 electrodes.