The program is intended for simulation of kinematics and dynamics of planar and spatial mechanical systems. The program is intended for using by students and teachers for educational purposes as well as design engineers for express analysis of designed mechanisms in their everyday work. It does not need from the user any special knowledge and operates with well-known for any design engineer terms and ideas. UM Lite supports data import from SolidWorks, Autodesk Inventor and Kompas-3D. From this point of view UM Lite may be considered as an inexpensive application for on-the-fly kinematical and dynamical analysis of designed mechanisms. The program is oriented to practical engineers, students and teachers; in other words it is oriented to all people who are involved in problems of dynamics of machines and mechanisms. Mechanical systems are described by means of representing them as systems of rigid bodies connected by various kinematical pairs and force elements, so-called multibody systems. Online animation of motion and plots of dynamical performances are available during simulation. There are lots of measurable dynamical performances of mechanical systems: linear and angular coordinates, velocities and accelerations, active forces and moments, reaction forces etc.