COMSOL Multiphysics is the fully-integrated multiphysics simulation environment developed by COMSOL AB, Sweden. COMSOL Multiphysics includes the COMSOL Desktop graphical user interface (GUI) and a set of predefined user interfaces with associated modeling tools, referred to as physics interfaces, for modeling common applications. A suite of add-on products expands this multiphysics simulation platform for modeling specific application areas as well as interfacing with third-party software and their capabilities. COMSOL Multiphysics is required to run any of the add-on products. The physics-based modules augment the core physics interfaces of COMSOL Multiphysics and provide additional interfaces for electrical, mechanical, fluid flow, and chemical applications. Any number of modules can be seamlessly combined to handle challenging multiphysics applications. The fully-integrated environment allows for a unified modeling workflow irrespective of the simulation task. The multipurpose add-on products enable optimization and particle tracing, and grant access to a large library of material properties. COMSOL software integrates seamlessly with third-party programs, such as industry-standard CAD tools, through the interfacing add-on products.