RF power-handling capacity of micro-electromechanical capacitive switches was modeled by multiphysics finite-element analysis. Coupled electromechanical, electrothermal and thermomechanical models were constructed by using commercially available software. Simulations by using the models were validated by small- and large-signal RF measurements. The measurements showed that the power-handling capacity of the switches depended on not only the properties of the membrane (the movable part of the switches), but also the substrate properties and the circuit environment. These effects were captured in a compacted model, which could be used to guide the improvement of the power-handling capacity of the switches.