calculator
Time Duration Calculator
Use the time duration calculator to find elapsed hours, work hours, shift length, study sessions, and overnight time ranges from HH:MM inputs.
Calculate elapsed time for work shifts, study blocks, travel windows, overnight schedules, project logs, and simple time-card checks.
Result
How it works
Enter both clock times
Use 24-hour HH:MM values for the start and end local clock times. Confirm the source schedule before calculating because this tool does not attach a date or time zone to either value.
Choose the duration mode
Select Same day or Overnight intentionally. Overnight adds 24 hours only when the ending clock time is earlier than the starting clock time; it does not represent intervals of 24 hours or more.
Subtract breaks and read the result
Enter break minutes only when they should be removed from the gross duration. Compare total minutes, hours plus minutes, and decimal hours before copying the format your worksheet or invoice expects.
Verify dates and official rules
Check the actual dates, daylight-saving or time-zone changes, required break policy, overtime rule, and payroll or invoice rounding method with the responsible source.
Examples
Work shift
Input: 09:15 to 17:45 with 30 break minutes
Output: 8 hours, 480 total minutes
Short meeting
Input: 10:00 to 10:45
Output: 45 minutes, 0.75 decimal hours
Study block
Input: 19:10 to 21:40 with 10 break minutes
Output: 2 hours 20 minutes
Overnight shift
Input: 22:30 to 01:15 overnight with 15 break minutes
Output: 2 hours 30 minutes
Show the midnight calculation
Input: 23:40 to 00:25, Overnight, 10 break minutes
Output: 20 minutes to midnight + 25 after midnight = 45 gross minutes; subtract 10 to get 35 minutes (0.58 decimal hours).
Travel window
Input: 06:05 to 08:50
Output: 2 hours 45 minutes
Contractor invoice
Input: 13:25 to 15:05
Output: 1 hour 40 minutes, 1.67 decimal hours
Event setup
Input: 07:30 to 11:15 with 20 break minutes
Output: 3 hours 25 minutes
Break audit
Input: 08:00 to 16:30 with 60 break minutes
Output: 7 hours 30 minutes after break subtraction
FAQ
What time format should I enter?
Use 24-hour HH:MM format, such as 09:00, 17:30, or 22:15.
Does 09:00 to 09:00 mean a full day?
No. Equal times are rejected, including in Overnight mode. A later ending clock time such as 10:00 is treated as a same-day difference even with Overnight selected, so do not use this tool to represent a 25-hour interval.
Can the calculator handle overnight times?
Yes, for a range that crosses midnight and ends at an earlier clock time. Overnight adds 24 hours only to a negative clock-time difference. It does not model dated intervals of 24 hours or more.
What happens if the end time is earlier than the start time?
Same-day mode returns a validation error. Overnight mode treats the end time as the next day.
How are break minutes handled?
Break minutes are subtracted from the gross duration. Break minutes must be zero or greater and less than the total duration.
What if the break is longer than the time range?
The tool rejects that input because a break longer than the gross duration would create a negative elapsed time.
Does this calculate payroll?
No. It calculates elapsed time only. Payroll, overtime, rounding, labor rules, official time sheet requirements, and local compliance policies should be checked with the responsible source.
Does it include dates or time zones?
No. This tool uses time-of-day inputs only and does not include dates, time zone conversions, daylight-saving changes, or business rules.
Why show decimal hours?
Decimal hours are useful for time sheets, invoices, and planning notes when a system expects values like 2.5 hours.
Can I use it for meetings or study sessions?
Yes. It is useful for everyday elapsed-time checks as long as you do not need official payroll or compliance logic.