Conventional and reverse approaches to transformer design are presented in this paper. The first uses device ratings to determine the sizes of the core and windings. In the reverse approach, the physical characteristics and dimensions of the windings and core are the specifications. By manipulating the amount and type of material actually to be used in the construction of the transformer, its performance can be determined. Such an approach is essentially the opposite of the conventional transformer design method. Both design methods are applied to two sample high voltage transformers. The measured performances of the as-built transformers highlight the limitations in using the conventional method, which are overcome using the reverse approach.