Time Duration Calculator
Calculate the exact time duration between two times in hours, minutes and seconds. This free calculator also handles overnight time ranges that continue into the next day.
Start Time
End Time
09:00:00 to 17:00:00
How to Use the Time Duration Calculator
- Enter the starting hour, minute and second.
- Enter the ending hour, minute and second.
- Use the 24-hour time format, where 17:00 represents 5:00 PM.
- Check End time is on the next day when the time range continues past midnight.
- Click Calculate Duration.
- Review the duration in hours, minutes and seconds.
- Check the total hours, total minutes and total seconds.
- Use Swap Times to exchange the starting and ending times.
- Click Reset to restore the default values.
How Is Time Duration Calculated?
The calculator converts the starting time and ending time into seconds and subtracts the starting value from the ending value.
Each hour contains 60 minutes, and each minute contains 60 seconds. Therefore, one hour contains 3,600 seconds.
When the end time occurs on the following day, the calculator adds 24 hours to the ending time before calculating the difference.
Total Hours, Total Minutes and Total Seconds express the same duration in different units. Decimal hours are not clock notation: 7.75 hours means 7 hours plus 0.75 x 60 = 45 minutes.
Worked Time Duration Examples
Same-day example: enter 09:15:30 and 17:45:45, with the next-day box unchecked. The duration is 8 hours, 30 minutes and 15 seconds. Total Hours is 8.504167, Total Minutes is 510.25 and Total Seconds is 30,615; decimal hours are rounded to six decimal places.
Overnight example: enter 22:30:00 and 06:15:00 and check End time is on the next day. There are 1 hour and 30 minutes before midnight and 6 hours and 15 minutes after midnight: 7 hours and 45 minutes total. The totals are 7.75 hours, 465 minutes and 27,900 seconds. Leaving the box unchecked produces an error.
09:00:00 to 09:00:00 is zero seconds without the next-day option, but 24 hours with it checked. Check the box only when the end time belongs to the following calendar day.
This calculator measures elapsed clock time only. It does not account for dates, time zones, daylight-saving changes or unpaid breaks.
How do I calculate the duration between two times?
Enter the starting and ending hours, minutes and seconds, then click Calculate Duration. The calculator will display the elapsed time and its equivalent in total hours, minutes and seconds.
What time format should I use?
The calculator uses the 24-hour format. Hours must be entered from 0 to 23. For example, 17:30 represents 5:30 PM.
Can the calculator handle overnight time durations?
Yes. Check the End time is on the next day option when the ending time occurs after midnight on the following day.
Can I calculate a duration that includes seconds?
Yes. You can enter hours, minutes and seconds for both the starting and ending times to calculate a precise duration.
What are total hours, total minutes and total seconds?
These results convert the complete duration into a single unit. For example, two hours equals 2 total hours, 120 total minutes or 7,200 total seconds.
Does the calculator account for breaks?
No. The calculator measures the complete elapsed time between the two entered times. Any unpaid or scheduled breaks must be deducted separately.
Does daylight-saving time affect the calculation?
No. This calculator compares entered clock times only and does not use a date, location or time zone. Daylight-saving changes are therefore not included.
Can I calculate durations longer than 24 hours?
Yes, with End time is on the next day checked. The maximum possible result is 47 hours, 59 minutes and 59 seconds, from 00:00:00 to 23:59:59 on the following day. It cannot represent an end time two or more days later.
What does the Swap Times button do?
The Swap Times button exchanges the starting and ending time values. The next-day option is cleared automatically so you can review the new time order.
Can I use this calculator for work hours?
Yes. It can calculate elapsed work time between a starting and ending time, but you must manually account for lunch breaks, unpaid breaks or multiple work shifts.
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