Time Calculator
Add or subtract hours, minutes and seconds, or find the time after adding hours to a clock time.
Quick answer: Enter durations and choose plus or minus. For example 1 h 30 min + 2 h 45 min = 4 h 15 min. To find a clock time, 9:00 AM plus 2 h 30 min is 11:30 AM.
How to use it
- Type hours, minutes and seconds on each row, and choose + or −.
- The total shows as hours:minutes:seconds, in decimal hours, minutes and seconds. Press Add a row for more.
- In the clock box, pick a time of day and add or subtract hours and minutes to see the new time.
Handy facts
| Unit | Equals |
|---|---|
| 1 hour | 60 minutes, 3,600 seconds |
| 1 day | 24 hours, 1,440 minutes |
| 1 week | 168 hours |
| 15 minutes | 0.25 hours |
| 45 minutes | 0.75 hours |
Adding hours and minutes by hand
Add the minutes first. If they reach 60 or more, carry 1 hour for each 60. Then add the hours. For example 2 h 45 min + 1 h 30 min: minutes 45 + 30 = 75, which is 1 h 15 min. Hours 2 + 1 + 1 = 4. The answer is 4 h 15 min.
What people use it for
- Adding up work or study time
- Planning a schedule or a trip
- Cooking and baking times
- Video and audio lengths
- Checking a timesheet
Questions
How do I add hours and minutes?
Add the minutes, carry any full 60 minutes into the hours, then add the hours. The calculator does this for you.
How do I subtract time?
Set the row to minus. The total can go below zero and is shown with a minus sign.
How do I add hours to a clock time?
Use the clock box: choose the start time, plus or minus, and the hours and minutes.
How many seconds are in an hour?
3,600.
Is it free?
Yes. No sign-up, no install and no limit.
Is anything saved or sent?
No. Everything runs in your browser. Only your own best score, where a page shows one, is kept on your device.
Last updated 2026-10-24. Free to use, no sign-up. Made by ficklestudio26.