<p>Ki-67 scoring is of essential importance in the evaluation of breast cancer. We evaluated a Ki-67 algorithm as a decision support tool to improve accuracy for pathology residents. We retrospectively evaluated Ki-67 scores on whole slide images (WSI) obtained from 156 consecutive breast cancer patients. Two senior pathologists determined the 2.1 mm² hotspot to be evaluated. Ki-67 scores from senior pathologists were compared with results generated by the algorithm, results from 10 pathology residents, and results from pathology residents with the assistance of the algorithm. In addition to numerical results from the algorithm, residents were also presented with a visual representation of nuclei that were counted and excluded. Statistical analysis was performed using Wilcoxon and intra-class correlation (ICC) tests. The mean Ki-67 scores from senior pathologists and the algorithm were 23 ± 18 and 24 ± 18, respectively (ICC, 0.98). Ki-67 scores from the residents were 19 ± 16 and 22 ± 16, without and with input from the algorithm, respectively. With input from the algorithm, residents’ scores were significantly closer to those obtained by senior pathologists (<i>p</i> = 0.008). Residents modified their scores in 53.8% of the cases where 74% of the better scores were characterized by an increase in the original scores. The results obtained by the Ki-67 algorithm were highly correlated with those assessed by senior pathologists. We demonstrated that the algorithm may serve as a decision support tool for residents to align their results with those of senior pathologists.</p>