Computing Regular Rate of Pay - Salaried Employee Working a Fixed Workweek of 40 Hours
If an employee is employed solely on a weekly salary basis, the regular rate is determined by dividing the salary by the number of hours that the salary is intended to cover. 29 C.F.R. § 778.113(a).

Example:
If an employee is paid a salary of $400 a week to work 40 hours, the regular rate of pay is $10 an hour. If the employee works 48 hours in one week, the employee is entitled to an overtime premium of $15 per hour, which amounts to $120 (8 hours X $15 = $120).