Nowadays there are lots of methods using three-dimensional or quasi three-dimensional CFD analysis. Unfortunately, this approach is still very demanding, so that quick preliminary design algorithms have still its importance, even though simplified analytical model of radial compressor gives less accurate results. Obtained results can be used in later stages of the radial compressor (RC) design, such as definition of spatial impeller geometry and CFD computation. The article presents the influence of input parameters in the radial compressor design algorithm on the efficiency. The assembled mathematical model of RC is derived from the basic laws of continuum mechanics and can be used for a quick assessment of the preliminary design concept of the RC. A sensitivity analysis is performed on input parameters to select parameters that have the dominant effect on the monitored performance indicators. On the basis of the sensitivity analysis, a multicriteria optimization process was assembled to increase the performance parameters.