Find the difference between two times, or add and subtract hours and minutes from a starting time.
If the end time is earlier than the start time, this assumes it falls on the next day.
This tool covers the two things people most often need to work out by hand: the gap between two clock times, and what time it will be after adding or subtracting a duration. Both just come down to converting everything to minutes, doing the arithmetic, and converting back to a readable clock time.
Use "time difference" when you have two points in time and want to know how much time sits between them - clocking in and clocking out, or the length of a meeting. Use "add or subtract time" when you have one starting time and a duration - for example, "I start driving at 2:20 PM and the trip takes 3 hours 50 minutes, what time do I arrive?"
If an end time is earlier in the clock than the start time - like starting at 10:30 PM and ending at 6:15 AM - this calculator assumes the end time falls on the next day and adds 24 hours before subtracting, rather than returning a negative number. The same logic applies in reverse when subtracting a duration pushes the result past midnight into the previous day.
A shift from 9:15 AM to 5:45 PM comes out to exactly 8 hours 30 minutes. A shift that starts at 10:30 PM and ends at 6:15 AM the next morning is 7 hours 45 minutes, since the calculator adds a day to the end time before subtracting. On the add/subtract side, starting at 2:20 PM and adding 3 hours 50 minutes lands at 6:10 PM; starting at 8:15 AM and subtracting 9 hours 30 minutes rolls back into the previous day, landing at 10:45 PM.
How do I calculate hours worked between a start and end time?
Use the "time difference" mode, enter your clock-in time as the start and clock-out time as the end, and the calculator returns the total hours and minutes worked - including handling overnight shifts automatically.
What happens if my end time is earlier than my start time?
The calculator assumes the end time is on the next day and calculates the difference accordingly, rather than showing a negative number - this is the normal case for overnight shifts.
Can I add or subtract more than 24 hours?
Yes - enter any number of hours in the hours field, even hundreds. The result will show the correct time of day along with how many days forward or back that lands.
Does this handle AM/PM automatically?
Yes - enter times using your device's normal time picker, and results are always displayed with AM/PM for clarity.
How is this different from a stopwatch or elapsed-time timer?
A stopwatch measures time as it passes in real time, starting from the moment you press start. This calculator works with times you already know or plan to use - useful for scheduling or reviewing past hours rather than timing something happening right now.
Can I use this for payroll or timesheet calculations?
It works well for calculating hours on a single shift. For adding up multiple shifts across a pay period, you'd need to run each shift through separately and add the totals together.
Why does the result sometimes say "previous day" or "next day"?
Clock times alone don't specify which calendar day they fall on. When a calculation crosses midnight - either because an end time is earlier than a start time, or because subtracting a duration pushes the result past 12:00 AM - the calculator notes that shift so the result isn't misread as landing on the same day.