Duration Calculator
Add up a list of durations, or subtract some, without juggling carries by hand. Enter each duration in hours, minutes and seconds, set the row to add (+) or subtract (−), and the running total appears instantly — normalized to h:m:s and also shown as decimal hours, total minutes and total seconds. Great for timesheets and billable hours, totaling video clip or lap times, working out how long a set of tasks takes, or any time-on-time arithmetic. A negative total is shown with a minus sign. Everything is computed locally in your browser.
2:15:30
Total hours: 2.2583
Total minutes: 135.5
Total seconds: 8,130
How to use
- Enter each duration's hours, minutes and seconds.
- Click the +/− button on a row to add or subtract that duration.
- Add as many rows as you need; read the total in h:m:s and the decimal forms below.
Frequently asked questions
- Can I subtract durations?
- Yes. Click the green + button on any row to switch it to a red −, and that duration is subtracted from the total. The result can go negative, shown with a leading minus.
- What are the decimal forms for?
- Total hours (e.g. 2.25) is handy for billing and pay; total minutes and total seconds are useful for exports, scripts or further math.
- Do minutes and seconds need to be under 60?
- No. You can enter 90 minutes or 200 seconds and the total normalizes correctly — the h:m:s result always carries into the right units.
- Is anything sent to a server?
- No. All the arithmetic runs in your browser; nothing is uploaded.
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