California Labor Code section 510(a) provides that the first 8 hours of work on the seventh consecutive workday in a workweek will be paid at time and one half, and all time after that on that seventh consecutive day will be paid at double time.  That is clear enough.  What is sometimes unclear is when a workweek starts and ends.  Under California law, the employer has broad discretion to set the days included in its own workweek.  For example, if the employer sets the workweek as Sunday to Saturday, an employee who works seven consecutive days from Tuesday to Monday is not entitled to section 510(a) premium pay because she has worked only 5 days in one workweek and 2 days in a different workweek.  However, an employer’s discretion to set its own workweek is not unlimited.  That is, and as held in the recent case of Seymore v. Metson Marine, Inc. (decided on April 14, 2011), an employer may not designate its workweek in a manner that is designed primarily, or solely, to evade overtime compensation.  Put another way, an employer may not engage in subterfuge or artifice designed to evade overtime laws.  See Huntington Memorial Hospital v. Superior Court (2005) 131 Cal.App.4^th 893.  Thus, when an employer designates its workweek, it is safest if (i) its workweek is the same for all of its employees, and (ii) the employer can point to a business reason other than avoiding overtime pay that supports its choice of workweek.  –Adam K. Treiger