A management system includes: a management server; one or more image forming apparatuses that notify the management server of information on a remaining amount of toner; and one or more terminals, in which the management server makes a toner remaining amount history by combining the information on the remaining amount of toner with time and date information, detects, based on the toner remaining amount history, that toner replacement has been performed when an increase rate of the remaining amount of toner exceeds a threshold value, and determines, based on the contract value, whether the remaining amount of toner before the toner replacement is not more than the contract value when the toner replacement is detected, and notifies the one or more terminals of that the performed toner replacement corresponds to a contract violation when the remaining amount of toner before the toner replacement is more than the contract value.