A program for the interactive design of elliptic approximation functions on personal computers 1s presented. The use of non-classical el1iptic functions and arithmetic-geometric iterations results in a substantial reduction in computational costs when compared to classical numerical methods. In addition, sinee no compromise approximations are made, unusually accurate results are abtained. Moreover, sinee the elliptic function formulation is not avoided, a close parallelisrn between this formulation and the classical one is possible.