Abstract: An expected wait time calculation system generates an expected wait time value representing a time duration expected to elapse before a subject client is connected to a resource for servicing. The expected wait time calculation system comprises an interface to a work force management system for obtaining an indicator of a quantity of resources available for servicing clients. An interface to a queuing system obtains an indicator of a queue position of the subject client. A FIFO array stores a plurality of measured time intervals, each representing a time period between two successive resource queue decrement events. The measured time intervals may be stored in a chronological order. An average time interval, or rate, calculator determines an average time interval by calculating an average of a selected quantity of those most recently measured time intervals from the FIFO array or a rate by dividing a unit of time by the average time interval.