Purpose: To evaluate the STONE score for success rate of PCNL. Materials and methods: This study prospectively included 445 patients undergoing PCNL and STONE score was calculated using pre-operative NCCT. All the cases were done by standard technique in prone position and post-operative complications were classified according to modified Clavien grading system. Results: The STONE score inversely correlated with the stone free rate, i.e. higher the STONE score, lower was the stone free rate (p value 0.0002). Among the individual components of the score, stone free rate correlated with the stone size (p value < 0.05) and number of calyces involved (p value < 0.05). The STONE score further correlated with the fluoroscopy time, operative duration and duration of post-operative hospital stay (p values <0.01). The STONE score grouped into low, intermediate and high further correlated with the complication rate (p value 0.03). Conclusion: The STONE nephrolithometry score is a simple and easily reproducible system based on NCCT scan to classify the severity/ complexity of renal calculi and can be used for proper patient counseling about stone free status.