Software development projects are known for inaccuracies associated with elapsed time and total cost estimates. Our research has investigated the use of Data Envelopment Analysis (DEA) as a tool for providing meaningful benchmarking of software development project team performance. This relates the time spent on the different phases of a development project to the complexity of the system as defined by its function point count and its user-base. This paper further describes an extension to this research to facilitate its use as a project estimation tool prior to actual commencement of a software development project. The result of this research is a stand-alone tool that allows project managers to assess their estimates against completed projects.