A system and method for calculating the amount of space that a user will be required to lease in various office buildings and providing a comparison so that the user can make educated decisions and pre-qualifications as to whether the building will be a viable leasing option for the user. In so doing, the system and method provide the user with relative values and target rental rates of the office buildings by considering the buildings' efficiency and corresponding amount of space the tenant will be required to lease. The calculated relative values and target rental rates may be used by tenants to evaluate building choices for leasing. The system may be configured on a network computer system or a standalone computer.