Time Calculator
Add or subtract hours and minutes from a clock time to find what time it will be.
Add or subtract time
Pick a starting time, a duration, and an operation.
Result
Resulting time
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Formula used
The starting time and duration are both converted to total minutes, added or subtracted, then converted back into a clock time — wrapping across midnight as needed.
Example: 10:30 PM + 3 hours 15 minutes = 1:45 AM (+1 day).
How to use this calculator
- Select the starting time.
- Choose Add or Subtract, then enter the number of hours and minutes.
- Press Calculate to see the resulting time.
FAQ
Frequently asked questions
How do I add hours and minutes to a time?
Convert both the starting time and the duration to total minutes, add them together, then convert back to hours and minutes, wrapping past midnight if needed.
What happens if the result crosses midnight?
The calculator shows how many days forward or backward the result lands on, alongside the resulting clock time.
Can I subtract a duration instead of adding one?
Yes, choose "Subtract" from the operation menu.
Does this handle durations longer than 24 hours?
Yes, any number of hours is supported — the day count will simply increase accordingly.