Additive models for molecular polarizabilities and volumes are created by fitting to data for 298 molecules. Tests on data for the 1641 organic molecules in the TABS database show that the best models have median absolute errors of 2.3% for the polarizability and 1.3% for the volume. Bonding lowers the volume in all 1641 molecules. (C) 2014 Elsevier B.V. All rights reserved.