How to Calculate the Time Between Two Times
Work out hours and minutes between two times, including overnight shifts.
The simple method
Convert both times to minutes since midnight, subtract the start from the end, then convert back to hours and minutes. For 9:15 to 17:45: 17:45 is 1065 minutes, 9:15 is 555 minutes, so the difference is 510 minutes — that’s 8 hours and 30 minutes.
Handling times past midnight
If the end time is earlier than the start time, the span crosses midnight. Add 24 hours (1440 minutes) to the end before subtracting. A shift from 22:00 to 06:00 is 8 hours, because 06:00 counts as the next day. A duration calculator handles this automatically.
Why it’s useful
Working out durations is essential for timesheets, billable hours, shift lengths, cooking and study sessions. Doing it by hand is error-prone with the 60-minute (not 100) rollover, so a calculator that converts to minutes and back keeps it accurate.
FAQ
How do I add up hours and minutes correctly?+
Remember there are 60 minutes in an hour, not 100. Convert everything to minutes, do the maths, then divide by 60 for hours and take the remainder as minutes.