This paper outlines a method of determining axially symmetric field distributions, where the shape of the insulation involved tends to be complex. Finite-difference techniques form the basis of the method which is illustrated by examples. Programming methods to reduce labour, computing time and costs are outlined, and a flow diagram of the general program is given. Accuracy and time saving are indicated by comparing the computed field distributions between concentric cylindrical electrodes and rotational hyperboloidal electrodes with the exact analytical solution of these distributions.