FEBio (finite elements for biomechanics) is a software package for finite element analysis and was specifically designed for biomechanics applications. It was developed at the Musculoskeletal Research Lab at the University of Utah. FEBio offers modeling scenarios, constitutive models and boundary conditions that are relevant to numerous research areas in biomechanics. Users can solve 3D large deformation solid mechanics as well as solid-fluid (as in porous media) problems. FEBio supports both quasi-static and dynamic analyses. A more detailed overview of FEBio's features follows below.