Calculating elapsed clock time

Convert each clock reading into minutes after midnight, then subtract the start from the end. A period from 09:20 to 11:05 lasts 105 minutes, or 1 hour 45 minutes.

Overnight periods

When the end occurs on the following day, add 24 hours to the end time before subtracting. From 22:30 to 06:15 the next day is 7 hours 45 minutes.

Clock time versus working time

The result is continuous elapsed time. It does not subtract meal breaks, pauses, or unpaid periods. Add or remove those intervals separately when calculating working hours.

Check an overnight result

For a start of 21:50 and an end of 05:20 the next day, split the period at midnight: 2 hours 10 minutes before midnight plus 5 hours 20 minutes after midnight equals 7 hours 30 minutes. If “same day” were selected instead, the end would precede the start and would not describe that shift. Breaking a result at midnight is an easy independent check and makes an incorrect day selection obvious.

When dates or zones are required

Use this calculator only when both entries are ordinary clock readings in the same time zone and the period is no longer than one day. Use the date-difference tool for whole calendar days. For a flight, remote meeting, daylight-saving change, or timestamped system event, retain the date, named time zone, and UTC offset; the same displayed time can represent different instants. Round only after subtracting, especially when another system bills in six-, ten-, or fifteen-minute increments.

This tool uses clock readings without dates or time zones. It does not account for daylight-saving transitions, leap seconds, or changes of location.