Systems and methods are disclosed for scheduling overtime and time-off for a workforce. In one embodiment, a method of workforce scheduling to handle an expected workload comprises, in an instruction execution system, receiving a first workforce schedule describing existing assignments of a plurality of workers to a plurality of shifts, each of the shifts being associated with a time range and a day; in response to a variance in the expected workload, selecting a modification to the first workforce schedule required to handle the variance in the expected workload during the day; and producing a second workforce schedule that modifies the length of at least one of the plurality of shifts to accommodate the modification to the first workforce schedule.