An employee's workweek is a fixed and regularly recurring period of 168 hours -- seven consecutive 24-hour periods. It does not have to coincide with the calendar week, but may begin on any day and at any hour of the day. Different workweeks may be established for different employees or groups of employees. Averaging of hours over two or more weeks is not permitted. Normally, overtime pay earned in a particular workweek must be paid on the regular pay day for the pay period in which the wages were earned. While a workweek customarily begins on Monday, that is not a legal requirement. However, an employer must follow a fixed pattern and cannot manipulate the start of the workweek to avoid paying overtime.