Sum times and durations
Add durations in minutes and seconds or hours, minutes and seconds.
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How we handle your data →How to use this tool
- Paste durations, one per line, in MM:SS or HH:MM:SS.
- Check trailing fields have two digits from 00 to 59.
- Add and inspect normalized duration, seconds and decimal hours.
An example you can verify
Add two session lengths expressed using different formats.
Example input
1:30:00 45:30
Expected result
2:15:30 8130 seconds 2.25833333333 decimal hours
The second row means 45 minutes and 30 seconds. Total duration exceeds two hours; it is not a clock time.
Sum times and durations: uses and practical guidance
Adding durations provides the accumulated length of sessions, videos or tasks without manually carrying minutes and seconds. Every row represents elapsed time rather than a clock reading. Output is normalized to hours, minutes and seconds, with total seconds and decimal hours also displayed. Two-field and three-field rows can be mixed, provided their meanings are respected. For example, a session lasting one hour and thirty minutes must be written 1:30:00. The shorter form 1:30 represents one minute and thirty seconds, making format choice part of the input rather than something inferred from context.
With two fields, the first is minutes and the second is seconds. With three fields, they are hours, minutes and seconds. The first field can exceed 59: 90:00 means ninety minutes, and 24:00:00 means twenty-four hours. Every field after the first must contain two digits between 00 and 59. A row such as 1:75:00 is rejected instead of being normalized through an assumption. Write 2:15:00 to express that duration. Written units, negative values, fractional seconds and separators other than colons are unsupported. Inspect the source format before pasting exported time values.
Decimal hours divide accumulated seconds by 3600. Do not read 2:30:00 as 2.30 hours: two and a half hours correspond to 2.5 decimal hours. Decimal display may require rounding, while the total seconds retain the exact integer sum. Before moving the result into another application, check whether it expects decimal hours, minutes or a duration format. A spreadsheet may interpret HH:MM:SS as a time of day and wrap its display after twenty-four hours. This tool does not apply that wrap, so totals longer than one day retain their complete hour count.
Blank rows are ignored, and the number of contributing durations is displayed. That count helps reveal a row omitted while copying from a report. The operation does not calculate intervals between dates, apply time zones, infer pauses or detect overlapping sessions. Two records describing the same time are both added if both are supplied. Select input consistent with your intended accumulation rule and retain the original list for review. Up to ten thousand rows and one hundred thousand characters are supported. Check representative known durations and the total seconds before using the result in a report or plan, particularly when the receiving application applies different time-format conventions.
Settings and limits
Enter one duration per line. MM:SS means minutes and seconds; HH:MM:SS means hours, minutes and seconds. Trailing minute and second fields must be between 00 and 59. The first field can exceed 59. Negative durations are unsupported. Maximum 10,000 rows.
Frequently asked questions
Does 1:30 mean one and a half hours?
No. Two fields mean one minute and thirty seconds. For one and a half hours, enter 1:30:00.
Is it free, and do I need to sign up?
Yes, it is free. You do not need to sign up, create an account or install an app, and there is no daily quota: open the tool and use it. The only limits are file sizes, which protect your device’s memory.
Is my data sent to any server?
No. What you type or paste is processed in your browser’s memory and is not sent to any server. You can check it in the browser’s Network tab or by going offline after the page has loaded.