The separation of circulating tumor cells from the bloodstream with high purity plays a crucial role in the treatment of cancer illness. Design and fabrication of cell sorters based on numerical models can lead to optimized cell sorters from throughput, purity, and size aspects. In this research, a symmetric sharp corner microchannel was designed and optimized to achieve a more compact cell sorter with high purity output based on a numerical model. Sharp corners in the microchannel generate centrifugal and inertial lift forces which cause particles (7.32 μm and 15.5 μm )   separation. The proposed numerical model was validated using experimental data. Using the proposed approach decreased the size of the device up to 19% while maintaining the purity level of 95.45%. These results will have impacts in designing compact cell sorters with high purity output for implantable applications.