The MOLPROJ software, based on the use of projection operators for quantifying the FERMO localization, was employed again successfully now for phenol protonation. The FERMO concept can be applied to find the protonation site for phenols. It was possible, even with different environments in which the experimental compounds were inserted, to have an idea of the preferred protonation site of these molecules. We obtained approximately 86% of correctness of the protonation sites using our theoretical methodology. It was also possible to rationalize a reaction with only experimental results that the reaction path depended on two factors: the size of the substituent and its position.