Time Difference Calculator
Calculate how many hours and minutes there are between two clock times — for example work hours, travel time or breaks.
How to use the time difference calculator
- Enter the start time.
- Enter the end time.
- Check "overnight" if the end time is earlier in the day than the start time because it's the next day (e.g. a night shift from 22:00 to 06:00).
How the difference is calculated
The calculator converts both times to minutes since midnight, and finds the difference:
Overnight: add 24 hours to the end time
The decimal number shows hours as a decimal (e.g. 8.50 h instead of 8 h 30 min), useful for timesheets and invoicing.
When the difference crosses midnight
A shift from 22:00 to 06:00 is eight hours, not minus sixteen. Subtracting the start time from the end time directly produces a negative number as soon as the period crosses midnight, and the fix is to add a full day whenever the end time is lower than the start time. This is the single most common error when working hours are calculated in spreadsheets, and it affects night shifts almost exclusively.
Daylight saving transitions create an extra trap twice a year. On the night the clocks go forward, the hour between 02:00 and 03:00 does not exist, and a shift spanning that night is one hour shorter than the clock times suggest. On the night they go back, the same hour repeats and the shift is one hour longer. This calculator works with plain clock times and does not account for that — see the time zone calculator for calculations where daylight saving is actually handled.
Frequently asked questions
What if the end time is earlier than the start time?
Check the "overnight" box if the shift extends into the next day. The calculator will then add 24 hours to the end time before calculating the difference.
Why does the calculator show time as a decimal number?
Many timesheets and payroll systems use decimal hours (e.g. 8.5 hours) instead of hours and minutes (8 h 30 min), so we show both.