Time Addition Calculator
Enter a start time and the hours and minutes to add to see the resulting time.
How time addition works
This calculator converts your start time to total minutes, adds the hours and minutes you entered, then converts the result back into a readable time, wrapping around midnight and tracking whether the result lands on the next day.
You can also enter negative hours or minutes to subtract time instead of adding it — the calculator handles both directions the same way.
Frequently asked questions
Can I subtract time instead of adding it?
Yes — enter a negative number in the hours or minutes field to subtract that amount from the start time.
What does the day indicator mean?
When adding time crosses midnight, the result shows a day indicator like (+1d) or (+2d) to show how many calendar days forward the resulting time falls, or (-1d) if subtracting pushes it to a previous day.
Does this work with 24-hour or 12-hour time?
The time picker uses your browser and operating system's preferred time format, but internally the calculator always works in 24-hour time to avoid AM/PM ambiguity.