Work with hours minutes seconds add or subtract times compute precise differences convert between units and sum durations instantly Includes timezone aware comparison daylight saving handling CSV and PDF exports an example table formulas explanation and a clear how to use section in a clean white interface with tips shortcuts keyboard support for users
| Task | Duration (HH:MM:SS) | Notes |
|---|---|---|
| Design review | 01:15:00 | Morning session |
| Development | 02:45:30 | Feature implementation |
| Break | 00:20:00 | Coffee |
| Testing | 01:10:15 | Regression checks |
Parsing converts inputs into total seconds using HH:MM:SS => seconds = H×3600 + M×60 + S. Addition and subtraction operate on total seconds then reformat to H:MM:SS with sign preservation. Unit conversion maps hours and minutes to seconds via 1 h = 3600 s and 1 min = 60 s. Difference uses epoch timestamps in the selected time zone to compute end − start, which correctly reflects daylight saving transitions within that zone.
seconds = H*3600 + M*60 + S
H:MM:SS = sign + floor(seconds/3600) : floor((seconds % 3600)/60) : seconds % 60
difference = timestamp(end, tz) - timestamp(start, tz)HH:MM:SS or just seconds. For differences, include full dates and pick the correct time zone.Use HH:MM:SS such as 02:30:15. You may also enter MM:SS or a plain integer representing seconds.
The sign is preserved. For example subtracting a larger duration yields a result like -00:10:05.
Yes. Timestamps are computed in your selected zone so DST gaps and folds are accounted for.
Yes. Click Download CSV to export all visible tables or Download PDF to generate a printable summary.
Yes. Use the Sum a List panel and paste one value per line. There is no hard limit besides browser memory.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.