Time Add & Subtract Calculator
Add or subtract hours, minutes, and seconds from any time. Get the resulting time instantly.
How to Add and Subtract Time
Adding or subtracting time requires working in a base-60 system for minutes and a base-24 system for hours. Unlike regular arithmetic, 75 minutes becomes 1 hour 15 minutes, and adding 3 hours to 22:00 wraps around to 01:00 the next day.
This calculator handles all wrapping automatically — so adding 5 hours to 22:30 correctly gives 03:30, not 27:30.
Common Use Cases for Time Calculation
Time addition and subtraction is useful for: scheduling meetings across time zones, calculating shift end times, figuring out arrival times, meal planning and cooking timers, and sports timing.
For example, if a flight departs at 14:45 and takes 7h 20m, it arrives at 22:05. Or if your shift starts at 07:00 and lasts 8.5 hours, it ends at 15:30.
24-Hour vs 12-Hour Time Format
This calculator uses 24-hour (military) time format. To convert: PM hours add 12 (3:00 PM = 15:00). 12:00 PM = 12:00. 12:00 AM = 00:00. Midnight wraps from 23:59 to 00:00.
For crossing midnight, the result will correctly wrap to the early hours of the next day.
Frequently Asked Questions
What is 3:45 PM plus 2 hours 30 minutes?
3:45 PM (15:45) + 2h 30m = 18:15 (6:15 PM). Enter 15:45 as start time, select add, hours=2, minutes=30.
What happens when time crosses midnight?
The calculator wraps around automatically. Adding 4 hours to 22:00 gives 02:00 (next day). The date change is indicated in the result.
Can I subtract time to find start time?
Yes — select 'subtract' to work backwards. If you need to be somewhere at 09:30 and the journey takes 45 minutes, subtract 45 minutes to find you need to leave at 08:45.