To determine the applicability of Moyer's probability tables in North Indian population of 16-18 year olds and to formulate a new regression equation for the same group of population. Evaluative Study. 1000 children aged 16-18 years were selected as sample for the measurement of mesiodistal widths of permanent mandibular incisors, maxillary and mandibular canines and premolars using study models. The recorded values were then subjected to statistical analysis. Software Package for Social Sciences (SPSS) software version 22.0. The actual widths of the canine and premolars showed highly significant differences in maxilla and in mandible (P < 0.001), compared to widths predicted by Moyer's probability table at 75th percentile. Moyer's mixed dentition analysis was not an accurate method for prediction in North Indian population as it showed overestimation of tooth sizes. Hence, new regression equation has been formulated for the same.