When overtime has to be paid. You'll receive overtime pay only for hours you actually worked. You won't get the overtime rate on sick pay, vacation pay, etc., unless that's your employer's policy.
Your employer doesn't have to pay you the overtime rate for work on weekends or holidays, unless your work on those days actually pushes you over 40 hours for the workweek. Many companies will pay you the overtime rate for working on this days, though. Also, overtime isn't based on the number of hours you work in a single day. If you work over 8 hours in one day, you won't receive overtime for the extra hours. You earn overtime pay only by working over 40 hours in a single workweek.
The workweek and overtime pay. When you calculate overtime pay, remember that each workweek stands on its own. Suppose you work 35 hours one week and 45 hours the next. Your employer can't average out these hour totals to deny you overtime pay. You must receive 5 hours of overtime pay for the extra time you worked during week two.