How to Calculate Time Duration Between Two Times
Time duration is the amount of time that passes between a start time and an end time. It is useful for work hours, study sessions, workouts, travel, appointments, and schedules.
Basic method
For a same-day duration, subtract the start time from the end time. For example, a session from 9:00 AM to 11:30 AM lasts 2 hours and 30 minutes.
What if the end time is after midnight?
A common problem occurs when an activity starts late at night and finishes after midnight. For example, 11:00 PM to 1:00 AM is 2 hours, not a negative duration. A time-aware calculator can handle this wraparound.
Use the free calculator
Our Time Duration Calculator lets you enter start and end times and calculates the elapsed duration for you.
Where time duration calculations help
- Employee work hours
- Study and focus sessions
- Exercise duration
- Travel schedules
- Meeting and appointment planning
Tip for accurate records
Use a consistent time format and decide whether your records use local time, a 12-hour clock, or a 24-hour clock. For activities crossing midnight, always verify the date as well as the time.
Frequently asked question
Can the calculator handle overnight durations?
Yes. If the end time is earlier than the start time, the calculator treats the end as occurring after midnight.