The analysis of a polymer obeying the log-normal molecular weight distribution (MWD) by means of size exclusion chromatography with dual concentration/light scattering or viscosity detection was theoretically examined. The relations between the theoretical and experimental values of MWD parameters and Mark-Houwink-Kuhn-Sakurada constants calculated by comparing viscometric, light scattering and effective linear calibrations to the universal one were calculated as functions of the instrument parameters (interdetector volume and resolution factor). The linearity of calibrations calculated from the dual trace directly or indirectly, by combining with the universal calibration, is preserved.