How the duration is calculated
Both times are converted to minutes since midnight, then subtracted. If the result is negative, 24 hours (1440 minutes) are added to account for crossing midnight.
- start hr / start min — start time, 24h clock (0–23 / 0–59)
- end hr / end min — end time, 24h clock (0–23 / 0–59)
More detail
Crossing midnight
If the end time is earlier than the start time, the calculator assumes the end time falls on the next day and adds 24 hours — useful for overnight or night-shift schedules, e.g. 22:00 to 06:00 comes out to 8 hours instead of a negative number.
Practical tip. Useful for timing night shifts, checking how long a meeting block runs, or converting a clocked-in/clocked-out pair into decimal hours for a timesheet.
Frequently asked questions
How many hours from 9:00 AM to 5:30 PM?
8 hours 30 minutes (510 minutes total). Enter start 09:00 and end 17:30 above to see it computed.
How many hours is a night shift from 10 PM to 6 AM?
8 hours. Since the end time (06:00) is earlier than the start time (22:00), the calculator adds 24 hours to account for crossing midnight.
Does this subtract lunch or break time?
No — it only calculates the total span between start and end. Subtract your break time separately if you need net working hours.
How do I get the duration as decimal hours instead of hours + minutes?
The Total hours output converts it automatically, e.g. 8 hours 30 minutes shows as 8.50 hours.