Boneyard Tools

Time Duration Calculator

Work out how much time passes between two clock times. Enter a start and end time to see the duration as hours and minutes, total minutes and decimal hours, with optional overnight handling.

How to calculate a time duration

  1. Enter the start time and end time in 24-hour HH:MM format.
  2. Leave cross midnight on if the shift runs past midnight, or turn it off for same-day times.
  3. Read the duration in hours and minutes, total minutes and decimal hours.

Examples

A standard work shift

Start 09:00, end 17:30
8h 30m (510 minutes, 8.50 hours)

An overnight shift

Start 22:00, end 06:00 with cross midnight on
8h 0m (480 minutes, 8.00 hours)

Frequently asked questions

How does it handle overnight shifts?

When the end time is earlier than the start time and cross midnight is on, the calculator adds 24 hours. So 22:00 to 06:00 returns 8 hours rather than a negative result.

What if I turn cross midnight off?

Then both times are treated as the same day. If the end is before the start it is rejected as invalid, which helps catch a typo like swapping the two times.

Can I get decimal hours for payroll?

Yes. Alongside hours and minutes you get the total in minutes and as decimal hours, so 8h 30m shows as 8.50 hours, ready to multiply by an hourly rate.

Do I have to use 24-hour time?

The inputs use 24-hour HH:MM, so 5:30 PM is entered as 17:30 and 1:00 AM as 01:00. The native time picker on most devices can switch between 12-hour and 24-hour display.

Does it include the end minute?

The result is the gap from the start time to the end time, so 09:00 to 09:30 is 30 minutes. It does not add an extra minute for the final clock tick.

Are my times sent to a server?

No. The calculation runs entirely in your browser, so the times you enter never leave your device.

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