Drug release from hydrophilic matrix tablets can be strongly influenced by the proportion of matrix forming polymer and the dimensions and geometry of the tablets. A complete two-factor, three-level factorial design, followed by multiple regression analysis and response surface methodology, was applied to investigate the influence of polymer level and tablet size on drug release kinetics from hydrophilic matrix tablets prepared with Carbopol 971P and Carbopol 71G. Tablet diameter, radius-to-height ratio, tablet surface area, and surface-area-to-volume ratio were evaluated as independent variables in terms of their applicability to characterize tablet size and geometry. The results indicate that it may be possible to control the rate of drug release by modifying the proportion of carbomer in tablets and tablet dimensions. The practical benefit of these simulations is to optimize the geometry and dimensions of a controlled release device and reduce the number of experiments involved in the development of new controlled release dosage forms.