In the case of histidine, we found the accuracy could be significantly improved by taking a consensus of the Amber14SB-H and CHARMM36m charge-scaled force fields which yielded an AUE of 0.24±0.04 pK and a Pearson correlation of 0.98±0.01. Even standing alone, Amber14SB-H with charge-scaling attained an accuracy of 0.50 ± 0.10 pK and correlation of 0.85 ± 0.06, while CHARMM36m with charge-scaling gave an accuracy of 0.71 ± 0.16 pK and correlation of 0.56 ± 0.15.