Duration Calculator
Add or subtract multiple time durations.
How to Use Duration Calculator
- 1Add time rows with hours, minutes, and seconds
- 2Click Calculate to sum all durations
- 3See the total in H:MM:SS format
About Duration Calculator
The Duration Calculator lets you add or subtract multiple time durations expressed in hours, minutes, and seconds. Add as many rows as you need, enter each duration in H:MM:SS format, and get the total time instantly.
This is the perfect tool for summing up work hours across a timesheet, totaling video clip durations for an editing project, or adding multiple race or lap times. The result is correctly normalized so values carry over between seconds, minutes, and hours automatically.
All processing runs in your browser with no server communication. There is no limit to the number of duration rows you can add, making it suitable for both short and lengthy timesheets.
Key Features of Duration Calculator
- Add multiple time durations in H:MM:SS format
- Automatic carry-over: 90 seconds becomes 1 minute 30 seconds
- Add as many rows as needed for large timesheets
- Remove individual rows to adjust your inputs
- Total displayed in both H:MM:SS and plain seconds
- Supports durations longer than 24 hours
- Instant running total as you add or edit rows
- Fully browser-based with no server dependency
Examples
Sum up daily work hours
Total the hours worked across five different tasks in a workday.
Input
1:30:00 + 2:45:00 + 0:30:00 + 1:15:00 + 0:45:00
Output
Total: 6:45:00 (6 hours 45 minutes)
Total video clip durations
Add up the lengths of multiple video clips for a playlist.
Input
0:03:45 + 0:07:20 + 0:05:55
Output
Total: 0:17:00 (17 minutes)
Common Use Cases
- Summing daily or weekly work hours from a timesheet
- Adding up video clip lengths for a YouTube playlist or film edit
- Totaling race lap times for sports analysis
- Calculating total practice time across multiple music sessions
- Adding up cooking or process step durations for scheduling
- Summing podcast episode lengths to plan a listening queue
Troubleshooting
Entering minutes or seconds greater than 59
Solution
Minutes and seconds should each be 0-59. The calculator will still process values over 59 and carry them over correctly, but standard input format is H:MM:SS.
Expecting to subtract durations in a simple minus mode
Solution
Duration subtraction is not directly supported. To subtract, calculate the total of the durations you want to keep and ignore the rows you want to remove.
Forgetting to enter seconds in the correct position
Solution
The format is Hours : Minutes : Seconds. Entering 1:30 will be interpreted as 1 hour 30 minutes (0 seconds). Include all three components for clarity.
Frequently Asked Questions
How many duration rows can I add?
You can add as many rows as needed. The calculator handles large timesheets with many entries and continues to display an accurate running total.
What happens if seconds exceed 60?
The calculator automatically normalizes values. If seconds reach 60 or more, they carry over into minutes, and if minutes reach 60 or more, they carry into hours.
Can the total duration exceed 24 hours?
Yes. The total is not limited to 24 hours. Weekly timesheet totals or long video compilations can easily exceed 24 hours and will be displayed correctly.
Can I subtract durations?
The tool is designed for addition. To effectively subtract, simply remove the row you do not want to include, and the total will update immediately.
How is the result shown?
The result is shown in H:MM:SS format and also as total seconds for use in further calculations.
Can I enter fractional seconds?
The calculator uses whole seconds. For sub-second precision, convert everything to milliseconds and use the Time Converter for the final result.
Is this useful for timesheet calculations?
Yes. Enter each work session as a separate row with the duration in H:MM:SS, and the tool totals all sessions for the day or week.
Is my data private?
Yes. All calculations run entirely in your browser. No durations or values are transmitted to any server.