FEMM is described as 'suite of programs for solving low frequency electro' and is an app in the Education & Reference category. There are three alternatives to FEMM for Windows, Linux and Mac. The best alternative is Agros2D, which is both free and Open Source. Other great apps like FEMM are GetDP (Free, Open Source) and QuickField (Freemium).
Agros2D is a multiplatform C++ application for the solution of partial differential equations (PDE) based on the Hermes2D library, developed by the group of Pavel Karban at the University of West Bohemia in Pilsen.