A computer program which yields values for the volumes, surface areas, and volume/surface area ratios of cell profiles is described for use on a desktop calculator (minicomputer). This program uses standard morphometric procedures, and incorporates data obtained from electron micrographs at two levels of sampling. The main program yields values for the 'average cell volume' at the tissue level of sampling. Two options at the cellular level of sampling are also included which yield values for the volumes, surface areas and volume/surface area ratios for the organelles. The first option allows an analysis of 'whole cells' containing equatorial profiles through the nucleus, while the second option permits a 'fractional' approach using segments of the cells. Finally, some of the advantages of the two options are discussed.