Due to the increasing size and complexity of software systems, software architectures have become a crucial part in development projects. A lot of effort has been put into defining formal ways for describing architecture specifications using Architecture Description Languages (ADLs). Since no common ADL today offers tools for evaluating the performance, an attempt to develop such a tool based on an event-based simulation engine has been made. Common ADLs were investigated and the work was based on the fundamentals within the field of software architectures. The tool was evaluated both in terms of correctness in predictions as well as usability to show that it actually is possible to evaluate the performance using high-level architectures as models.