The overtime threshold is determined by the length of the work period. For non-public safety employees the work period is always one week, and the overtime threshold is 40 hours. For law enforcement officers the work period may be longer.

Non-law Enforcement Officers
Includes dispatchers, clerks, secretaries, and civilian parking control officers.

• One-week work period threshold 40 hours overtime

Law Enforcement Officers

• One-week work period: overtime threshold is 43 hours
• Two-week work period: overtime threshold is 86 hours
• Four-week work period: overtime threshold is 171 hours
  29 C.F.R. § 553.230.

Once the number of hours actually worked in the work period exceeds the overtime threshold, the employee must be compensated at one and one-half times the normal rate of pay. It does not matter how many hours an employee works in any given day during the work period, whether the day fell on a holiday, or whether the work was on a regularly scheduled day off; overtime is calculated on the total number of compensable hours worked in excess of the overtime threshold for the work period.