A computer program has been developed to convert the notations of the Munsell, OSA-UCS, NCS, DIN, and Coloroid color order systems and the CIE, CIELAB, and CIELUV color specification systems. The development and structure of the program are outlined. Particular attention is given to the accuracy of the program and its associated database. In addition to its industrial applications, the program has been used to study research problems in linguistics and color science. It was designed to allow expansion as further combinations of illuminant, standard observer, and aim or actual definitions become possible.