Most available software on dynamics or kinematics is used to analyze the behavior of a mechanism. However, to start with, the Engineer has to `invent` a mechanism before he can analyze it. This is not a trivial task. With available methods and handbooks this can take several days if not weeks. Watt Mechanism Design Tool solves this problem. From specification of the required movement and constraints on pivot locations, transmission angles, dimensions, it searches and finds a variety of approximate or exact solutions within minutes. The user can interactively set specifications, evaluate the offered solutions and add or relax constraints.