Centrality defines the collision system size and serves as one of the main parameters for the characterization of relativistic heavy-ion collisions. In the first year(s) of operation, the MPD experiment will collect events with a rather wide z-vertex distribution (sigma ~ 40 cm). In this report, we are studying the MPD capabilities for centrality measurements in a wide range of z-vertex coordinates using the TPC and FHCAL detectors.