Partial reconfiguration (PR) on field-programmable gate arrays (FPGAs) enables multiple PR modules (PRMs) to time multiplex partially reconfigurable regions (PRRs), which affords reduced reconfiguration time, area overhead, etc., as compared to non-PR systems. However, to effectively leverage PR, system designers must determine appropriate PRR sizes/organizations during early stages of PR system design, since inappropriate PRRs, given PRM requirements, can negate PR benefits, potentially resulting in system performance worse than a functionally-equivalent non-PR design. To aid in PR system design, we present two portable, high-level cost models, which are based on the synthesis report results generated by Xilinx tools. These cost models estimate PRR size/organization given the PRR's associated PRMs to maximize the PRRs' resource utilizations and estimate the PRM's associated partial bitstream sizes based on the PRR sizes/organizations. Experiments evaluate our cost models' accuracies for different PRMs and required resources, which enable our models to afford enhanced designer productivity since these models preclude the lengthy PR design flow, which is typically required to attain such analysis.