Time calculator
Add or subtract time from a clock time, or find how much time falls between two times of day.
If the end time is earlier than the start time, it's treated as the next day.
Fill in the fields and press Calculate to see your result here.
How this calculation works
Adding or subtracting time converts everything to minutes, does the arithmetic, then wraps around a 24-hour clock (so 11:00 PM plus 2 hours correctly becomes 1:00 AM). Finding the duration between two clock times does the same wrap-around in reverse, and assumes the end time is on the next day if it is numerically earlier than the start time.
Worked example
A flight departs at 11:45 PM and lands 7 hours 50 minutes later: 11:45 PM + 7h 50m wraps past midnight to 7:35 AM the next day.
Tips
Crossing midnight is handled automatically
You don't need to figure out AM/PM math yourself — enter the times as shown on a clock and the wrap-around is handled for you.
Add more than 24 hours
Enter 30 hours to add a day and a half. The result shows the new clock time and how many days it moved.
Handy for shifts and travel
Use it to find when a 9-hour shift ends, or what time you land after a flight of a known length.
Results use 12-hour format
Your input may show a 24-hour picker depending on your device, but answers are displayed in AM/PM.
Frequently asked questions
Can I subtract more time than has passed since midnight?
Yes — subtracting time wraps back into the previous day the same way adding wraps into the next.
Does this handle dates, not just times of day?
For a specific number of days between two calendar dates, use the Date duration calculator instead — this tool works with times of day only.