Software effort estimation has become one of the most important concerns of software industries. Developers use effort estimation to ensure the quality of software systems can be delivered within time and budget. Current development tools for effort estimation based on UCP model help with automating the effort required for a software project. However, they offer no opportunity for future extension as a web-based application. Therefore, this paper describes a new web-based tool support for automating software effort estimation. The tool has been developed based on use case points model using rich internet application technology to improve the reusability of software effort estimation applications.