An interactive computer program GMAN has been developed to facilitate the generation and manipulation of coil geometry data bases required for three-dimensional magnetic field analyses. GMAN was designed specifically to be used in conjunction with the three-dimensional field analysis program EFFI developed at the Lawrence Livermore Laboratory. GMAN generates the coil geometry data elements from curves representing centerlines of windings. It can also be used to perform geometrical (symmetry) manipulations on the data elements. The design goal of the program is that it be versatile and easy to use so that the generation and modification of coil geometry data bases can be accomplished with a minimum amount of effort.