A model based on percolation theory has been set up to elucidate the relationship between relaxed complex Young's modulus, hardness and normalized solid fraction of pharmaceutical compacts. The relationship between the variables is non-linear over the whole range of the solid fraction of the compacts. However, in a semi-logarithmic representation linear relationships could be established in certain ranges of the solid fraction of the compacts. The semi-logarithmic plot of Young's modulus or hardness against the solid fraction is comprised of segments of straight Unes. The inflexions between the segments indicate a change in the consolidation behaviour as a function of the applied pressure, i.e. as a function of solid fraction of the compact. The number of these segments depends on the mechanical properties of the powder mix. In addition to the solid components, the mechanical properties are affected by the pore system. The straight line relationships allow extrapolations to be made to zero porosity thus furnishing the mechanical property of the soUd components. The model has been illustrated with single and binary solid component compact systems. Single and binary solid component powder systems behave similarly.