1. A computer-implemented system for tracking physical objects, comprising: pairs of associated identifiers and trackers; a dispenser to provide one of the identifier-tracker pairs to a user, wherein the user associates the tracker with a physical object and to receive the identifier from the provided pair; an identification module to identify the tracker associated with the received identifier; a tracker location determination module to determine a location of the tracker, comprising: a monitor module to monitor readers within a defined area; a plurality of readings comprising the tracker obtained from the readers; and a location calculation module to determine a location of the identified tracker based on the readings from a plurality of the readers; and an object location determination module to determine a location of the physical object based on the location of the identified tracker.