Add or subtract time
Add signed minutes to a clock time and see whether the result falls on another day.
Formula
New clock time = (clock seconds + minutes × 60) modulo 86,400
Clock time = 09:30 · Minutes to add or subtract = 90
How to use
- Enter the starting clock time.
- Enter positive or negative minutes.
- Read the new time and day change.
Examples
- 23:45 + 30 minutes = 00:15 on the next day.
Frequently asked questions
What does day change −1 mean?
The result is on the previous day.
Can I add more than one day?
Yes. Each 1,440 minutes moves the time by one full day.
Is daylight saving time included?
No. This is clock arithmetic with fixed 24-hour days.
Sources
Updated: