The absence of computational tools for the application of proportional theory in analysis and synthesis in design has been a persistent problem in the field of formal composition in architectural design. A computational tool, code-named here Hermes, is introduced as a tool for proportional studies based on the theory of the eleven proportional means. The analysis component of the application evaluates existing designs and provides statistical measures about the proportional structure of the design. The synthesis component of the application generates new designs from known ones with additional prescribed proportional properties. The analysis component is written in Autolisp and runs within AutoCAD. The synthesis component is written using the Genetic Algorithm Toolbox of Matlab and an AutoLisp application within AutoCAD. Both cases are built using extensively design optimization methodologies. The corpus of the designs for both analysis and synthesis has been selected from Palladio’s buildings to link this project to the long list of research projects that have tackled proportion using Palladio’s work as an exemplary body of work.