The study focuses on predicting the (nk) factor of the cone penetration test (CPT) using genetic programming (GP) and multi expression programming (MEP) techniques, highlighting the variability of the (nk) factor based on soil properties. Two software programs, GN7 and MEPX, were employed to analyze a data set consisting of 102 records, resulting in the GP methods achieving accuracies between 93% and 97%. The findings emphasize the effectiveness of these programs in correlating the (nk) factor with clay consistency limits while demonstrating the limitations of MEPX compared to GN7.