The workweek is a fixed period of 168 consecutive hours that recur on a consistent basis. The start and stop times and dates can be set by management, but they should be consistently applied. And whatever the workweek is defined to be, it should be listed in the employee manual to avoid confusion about which hours worked fall into which workweek, not only for payment purposes but also for the calculation of overtime.

It is unwise to alter the stated workweek, since it may be construed as avoidance to pay overtime. For example, assume a company has a history of requiring large amounts of overtime at the end of the month in order to make its delivery targets. Suddenly company management elects to change the workweek from Monday through Sunday to Wednesday through Tuesday right in the middle of the final week in a month, thereby reducing much of the overtime hours that employees would otherwise earn to regular hours. This would be a highly suspect change of workweek that might be construed by the government as a way to avoid overtime payments.

It is, however, perfectly legitimate for different workweeks to be assigned for different departments and locations. This is particularly common when a company is acquired and elects not to conform to the acquiree's workweek. If there are many of these acquisitions, a centralized payroll department may find itself tracking every conceivable variation on a workweek, all within the same organization.