Studies of M-component synthesis and metabolism, as well as clinical staging of multiple myeloma, have provided the basis for calculation of the total body tumor cell number and quantitation of response to treatment. Many of the calculations involved have been complex and have previously required the availability of a computer. The advent of programmable pocket calculators has permitted simplification of these programs for general clinical and investigative applications in studies of myeloma and related monoclonal gammopathies. In this paper we have included the background information and a clinical example of the use of the programmable calculator, as well as the logic steps and the calculator programs themselves, for several of the most useful programs for clinical staging and quantitation of response to therapy in IgG myeloma.