This manuscript described three methods for predicting the molecular mass of an analyte from its EI-MS spectrum, outlining their individual and combined utility towards inferring the molecular mass of an analyte. The precision of ensemble predictions was computed for 32 scenarios that consider various classifier values. While some scenarios were inadequately represented in the results to make general performance comments, the predicted molecular mass was almost always correct when all three predictions agreed. Continuing to expand and evaluate reference libraries will improve the performance of library-based predictions. Optimizing search parameters for specific applications and improving classification of predictions for decision-making is interesting and ongoing research.