Time Duration Calculator
This calculator works out exactly how much time passes between two clock times, showing the result in hours and minutes, as total minutes, and as decimal hours. Enter a start time and an end time using the time pickers, and the result updates instantly as you type. The main result shows the elapsed duration in plain hours and minutes, for example 8 hours 30 minutes, alongside the total minutes and the equivalent decimal hours, useful for payroll and timesheets since decimal hours multiply directly by an hourly rate. The calculator automatically handles durations that cross midnight: if you enter an end time earlier than the start time, such as a night shift running from 10:00 pm to 6:00 am, it assumes the period runs into the next day, adds 24 hours, and flags this with a note under the result. This makes it well suited to shift lengths, meeting durations, appointment gaps, or any stretch of time where you know the start and finish but need the exact length in a useful format. Use it for timesheets, checking whether a rostered shift meets minimum hour requirements, or converting hours and minutes into decimal hours for invoicing. Because the maths is simple subtraction of clock times, the result is exact rather than an estimate, though it does not account for unpaid breaks, which you would need to subtract yourself.
How the duration is worked out
Each time is converted to the number of minutes since midnight. The start is subtracted from the end to give the duration in minutes, which is then converted back to hours and minutes. If the end time is earlier than the start time, the duration is assumed to run past midnight, so 24 hours are added.
Worked example
A shift runs from 9:00 am to 5:30 pm. That is 540 minutes since midnight for the start and 1,050 for the end. The difference is 510 minutes, which is 8 hours and 30 minutes, or 8.5 decimal hours.
An overnight shift from 10:00 pm to 6:00 am has an end time earlier than the start, so 24 hours are added. The result is 8 hours.
Why decimal hours matter
Payroll systems usually multiply hours by an hourly rate, and that is easier with decimal hours than with hours and minutes. For example, 8 hours and 30 minutes is 8.5 hours, so at $25 an hour that shift is worth $212.50.
Frequently asked questions
Does it handle overnight shifts?
Yes. If the end time is before the start time, the calculator adds 24 hours, so an overnight shift returns the correct duration.
How do I convert minutes to decimal hours?
Divide the minutes by 60. So 30 minutes is 0.5 hours, and 15 minutes is 0.25 hours.
Who this calculator is for
This calculator is for anyone finding the duration between two times or dates, for scheduling, timesheets or planning.
What this calculator assumes
- The two times or dates you enter.
- Standard 24-hour and calendar arithmetic.
- It does not adjust for time zones or daylight saving unless stated.
- Results are shown in the units selected.
Related calculators
- Hours Calculator: add up hours and minutes.
- Work Hours and Timesheet Calculator: full timesheet with breaks.
- Time Calculator: add or subtract time.
- Business Days Calculator: working days between dates.