In this paper is presented a comparative evaluation in steady-state of three single-phase NPC multilevel inverters. The first is a five-level neutral point clamped (NPC) inverter based on multi-stage switching cell (MSSC); the second is also a five-level neutral point clamped (NPC) inverter based on interleaved cell (IC); and the third is a three-level neutral point clamped (NPC) inverter based on paralleled cell (PC). For this comparative purpose, the switching frequency is constant and the evaluated parameters are the volume of the heatsinks and the passive components, the total harmonic distortion (THD) of the output voltage, the power density and efficiency of each topology. Theoretical analyses, as well as simulation and experimental results obtained from 5kW prototype are presented.