According to the FLSA, nonexempt employees must receive overtime pay for hours worked in excess of 40 in a workweek, and at a rate not less than time and one-half their regular rate of pay.
Overtime pay must be calculated based on the total number of hours worked in each workweek, even when those workweeks are split between pay periods.
A workweek is a fixed and regularly recurring period of 168 hours, or seven consecutive 24-hour periods. The workweek does not have to coincide with the calendar week.
For reference, please click the below link that reviews overtime calculations for semi-monthly pay periods. https://webapps.dol.gov/elaws/whd/flsa/otcalc/i8example.asp