Date & Time
Time Calculator
Add or subtract hours, minutes, and seconds from a time, or measure duration between two clock times.
Time calculator
Result time
11:30:00
Same day.
Frequently Asked Questions about the Time Calculator
What can this time calculator do?
It works in three modes: add a duration to a start time, subtract a duration from a start time, or find the elapsed time between two clock times. All results are shown in hours, minutes, and seconds (HH:MM:SS).
How does it handle crossing midnight?
The calculator tracks day boundaries automatically. If adding time pushes the clock past midnight (00:00), it wraps the clock back to a 24-hour value and reports how many full days you crossed forward. Subtracting past 00:00 wraps backward and shows a negative day count.
Does the duration mode handle overnight shifts?
Yes. If the end time you enter is earlier than the start time (for example, start 22:00 and end 06:00), the calculator treats the end as the following day and returns the correct elapsed duration of 8 hours.
What time format should I use?
Enter times in 24-hour format as HH:MM (for example, 14:30 for 2:30 PM). Both single-digit hours like 9:00 and two-digit hours like 09:00 are accepted. Results always display as HH:MM:SS.
Can I add seconds, not just minutes?
Yes. In add and subtract modes you can enter hours, minutes, and seconds independently, so you can shift a time by any combination, such as 1 hour, 45 minutes, and 30 seconds at once. Duration mode accepts only HH:MM for the start and end times.