Time / Arithmetic
Time Calculator (Add and Subtract Hours and Minutes)
Add up and subtract times in hours, minutes, and seconds, such as video clips, laps, or hours worked, one per line, and get the total as h:mm:ss and in decimal hours, minutes, and seconds.
Time Calculator (Add and Subtract Hours and Minutes): Every line is turned into seconds, added or subtracted, and the total is written back as hours, minutes, and seconds. 1:45:30 + 0:32:15 + 2h 10m − 0:15:00 = 4:12:45, which is 4.2125 hours. Totals carry on past 24 hours instead of wrapping to the next day. Runs 100% locally in your browser with zero server file uploads.
- Category
- Time & calendar tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Add up durations such as video clips, laps, or work sessions, and subtract breaks: each line can be h:mm:ss, mm:ss, decimal hours or minutes such as 2.5h or 90m, or plain seconds. The total keeps counting past 24 hours rather than wrapping round, so 25:00:00 means twenty-five hours.
Adding minutes correctly
Minutes and seconds go up to 60, not 100, so 0:45 + 0:30 is 1:15, not 0:75. The calculator does the carrying; in decimal hours, 0:45 is 0.75 and 0:30 is 0.5.
For the time between two clock readings, such as 09:15 to 17:40, use the time duration calculator.
Worked example
A video made of clips of 3:42, 5:18, and 12:05, with a 0:30 section cut, runs 3:42 + 5:18 + 12:05 − 0:30 = 20:35, or 0:20:35.
To convert a 12-hour time to 24-hour, see the military time converter.
How to use it
- Type each time on its own line, as h:mm:ss, mm:ss, or forms like 1h 30m.
- Start a line with a minus sign to subtract it.
- Read the total and the same total in decimal hours, minutes, and seconds.
Privacy & limitations
Everything is calculated in your browser.
Related tools
Frequently asked questions
How do I enter 90 minutes?
As 90m, 1:30:00, or 1h 30m; plain numbers are read as seconds.
How do I convert to decimal hours for a timesheet?
The total is also given in hours: 7:45 is 7.75 hours.
How do I find the time between two clock times?
Use the time duration calculator, which counts from one time of day to another.
Free tool · runs in your browser · no account required