This paper emphasizes on the magnetic charge method to determine the magnetic force density due to mechanical deformation for nonlinear magnetic materials. For incompressible and nonlinear magnetic materials, theoretical expression for magnetic force density due to mechanical deformation generating from Korteweg-Helmholtz force density (KH), Kelvin force density (KV), and magnetic charge force density (MC) methods have been proven to be equivalent. The Maxwell stress tensor method (MX) and MC have been employed to calculate magnetic force density due to mechanical deformation. Numerical implementation of the equivalent magnetic charge method is quite simple, so the local force density for nonlinear material can be readily obtained. To exhibit validity and usefulness of the proposed method, an axisymmetric actuator and an electromagnet with highly saturated cantilever plate have been examined.