In this paper, real-time time-dependent density functional theory (RT-TDDFT) calculations of realistically sized nanodevices are presented. These microcanonical simulations rely on a closed boundary approach based on recent advances in the software package CP2K. The obtained results are compared to those derived from the open-boundary Non-equilibrium Green’s Function (NEGF) formalism. A good agreement between the “current vs. voltage” characteristics produced by both methods is demonstrated for three representative device structures, a carbon nanotube field-effect transistor, a GeSe selector for crossbar arrays, and a conductive bridging random-access memory cell. Different approaches to extract the electrostatic contribution from the RT-TDDFT Hamiltonian and to incorporate the result into the NEGF calculations are presented.