Overtime is defined as work in excess of 8 hours in a day or 40 hours in a workweek. Overtime also is work that is officially ordered and approved by your supervisor.
Regardless of tour, overtime hours of work in excess of 8 in a day are not included in computing hours of work in excess of 40 hours in an administrative workweek. (5 CFR 550.111 [a]  ).
Overtime is worked in 15 minute increments. Overtime may be worked only in increments of less than 15 minutes if the work situation is not controlled by the agency. Work of 7 minutes or less is rounded down to zero and work of 8 minutes or more is rounded up to 15 minutes.
Types of Overtime
There are three different types of overtime work:
Irregular or occasional,
Suffered or permitted.
What Is Irregular or Occasional Overtime?
Irregular or occasional overtime is work which is ordered and approved by your supervisor after the beginning of the administrative workweek.
Exception: If you are an employee with a first-8 or first-40 indefinite tour of duty, irregular overtime work occurs when you are called back to the work site after the completion of your workday.
Example: You work a tour of duty of Monday through Friday, 8 a.m. to 4:30 p.m. At 3:30 p.m. on the first Monday of the pay period, you are informed by your supervisor that you must stay and work until 6:30 p.m. to complete an assignment. This is your irregular or occasional overtime because your supervisor ordered it after the beginning of the administrative workweek.
What is Regular Overtime?
Regular overtime is work which is scheduled before the beginning of the administrative workweek and specifies the day(s), and time(s) that you and your co-workers, if applicable, are ordered to work.
Exceptions: If you are an employee with a first-8 indefinite tour of duty, then regular overtime is work that is continuous with and serves to extend your nonovertime hours. Work on subsequent days is irregular or occasional overtime unless it is ordered in advance of the administrative workweek.
If you are an employee with a first-40 tour of duty, then all overtime hours that do not meet the criteria for irregular or occasional overtime work are regular overtime hours.
Example: You work a tour of duty of Monday through Friday, 8 a.m. to 4:30 p.m. Your supervisor informs you on the second Friday of the pay period that you will have to work overtime on the first Monday of the next pay period from 4:30 p.m. to 6:30 p.m. This is regular overtime because it is ordered in advance of the administrative workweek and the time and day the overtime is to be worked is specific.
What is Suffered or Permitted Overtime?
Suffered or permitted overtime only applies to Fair Labor Standards Act-nonexempt employees. See the section covering this topic for additional information.