EReeRisk (Efficient Reengineering Risk) is a risk impact measurement tool which automatically identifies and measure impact of various risk components involve in reengineering process of legacy software system. EReeRisk takes data directly from users of legacy system and establishes various risk measurement metrics according to different risk measurement scheme of ReeRisk framework [1]. Furthermore EReeRisk present a variety of statistical quantities for project management to obtain decision concerning at what time evolution of a legacy system through reengineering is successful. Its enhanced user interface greatly simplifies the risk assessment procedures and the usage reaming time. The tool can perform the following tasks to support decision concern with the selection of reengineering as a system evolution strategy. [1] To establish promising risk measurement models for legacy system under evaluation. [2] To measure risk impact of specific risk component of legacy system under evaluation [3] To identity& establish various risk measurement index for risk impact measurement. [4] To establish and measure perspective and domain specific risk impact of legacy system. [5] To identify the source of risks and indicates how they affect impact of particular risk component. [6] To determine the validity of risk measurement models from field data.