One of the most interesting topics in the eld of human-machine interaction is workload. In this paper, by using information theory concepts, the baud rates generated in all subsystems of a generic simulator of piloting tasks were calculated; then, a unique numerical index, which determines an estimate of the overall workload, was extracted. To examine the e ectiveness of the presented criteria, three tests with di erent levels of Autopilot failure were designed in which existing workload was labeled based on the assumed baud rates. A group of subjects carried out these tests as pilots while recording their own ideas about perceived workload. Results con rmed that there were statistically signi cant di erences between the averages of scores assigned by subjects to the overall workload at three levels of di culty. Consequently, the proposed quantitative index was found e ective enough to determine workload levels in the simulator environment, thus facilitating the creation of the needed scenario noticeably.