Abstract: A system and method for modeling the size of a computer system. In one embodiment, the present invention receives selected workload information which indicates the expected performance requirements for a desired computer system. The present invention calculates the busy time and a utilization percentage for a central processing unit which is subjected to the selected workload. The present invention also calculates the minimum amount of memory and the mass storage requirements for a modeled computer system subjected to the selected workload and wherein the modeled computer system is equipped with the aforementioned central processing unit. In so doing, the present invention indicates the processor, memory, and mass storage requirements for a computer system without requiring that the computer system actually be constructed and tested.