Clock arithmetic
Time Calculator
Add or subtract hours and minutes from a clock time, including calculations that cross midnight.
Clock result11:30Added 2 hr 30 min
How this calculator works
Choose a starting clock time, enter a duration, and add or subtract it.
Clock results wrap across midnight automatically, so 23:30 plus 2 hours becomes 01:30.
The tool is arithmetic only. Where legal, payroll, holiday, timezone or jurisdiction-specific rules matter, the page states what is and is not included.
Frequently asked questions
Does the calculator handle the next day?
Yes. Clock time wraps after midnight. The result shows the resulting time; use the date calculator when the calendar date also matters.
Is this a timezone converter?
No. It performs local clock arithmetic and does not convert between time zones — see the Time Zone Converter for that.