Antibodies are the most common class of biologic drugs, but they have very high R&D costs. Antibody drugs require highly concentrated formulations, which can result in highly viscous solutions that are challenging to handle both in manufacturing processes and in end user injections. Currently, it is difficult to predict antibody viscosity. These challenges are only discovered late in drug development after there has been significant R&D investment. This invention is a new way of predicting antibody viscosity early in the drug development process, which will allow pharmaceutical companies to save R&D money by prioritizing low viscosity antibody candidates.