Res2Dinv and res3Dinv are powerful software packages for inversion of 2D and 3D ERT (DC) and IP data. The program offers a simple workflow from data import to inversion and visualization, while still offering full control over inversion parameters for advanced users. The programs are very flexible and can handle nearly every imaginable survey configuration, including topography, borehole and subsurface electrodes, spatially extended electrodes, arbitrary electrode locations, electrodes on and in water-bodies, and streamed electrode configurations, as well as all conventional configurations.