About this Time Duration Calculator
Time Duration Calculator measures the elapsed time between two clock times, including overnight intervals. If the end time is earlier than the start time, the calculator assumes the end occurs on the following day.
Formula or method
Duration = end time − start time; if the result is negative, the end is treated as the next day.
Example
22:00 to 01:30 equals 3 hours 30 minutes.
Common uses
- Calculate a work or study session length.
- Measure an overnight shift or travel interval.
- Check elapsed time between appointments.
How to use this tool
- Enter the values or text requested by the calculator.
- Choose units or options when the tool provides them.
- Select the calculation button and review the result.
- Use the formula, example and notes on this page to check whether the result fits your situation.
Important note
This version is intended for a single interval shorter than 24 hours.
Frequently asked questions
What happens if the end time is earlier?
The tool assumes the interval crosses midnight into the next day.
Can it calculate more than 24 hours?
No. Use a date-based calculation for multi-day durations.