Time Duration Calculator
Measure elapsed time or add and subtract hours, minutes, and seconds with DST-aware results in your browser.
Search by city or region. The selected zone determines daylight-saving gaps and repeated clock times.
Measure elapsed time
Compare two date-times in one zone and see the exact elapsed days, hours, minutes, and seconds.
Add or subtract elapsed time
Apply an exact number of hours, minutes, and seconds. If a DST boundary is crossed, the resulting wall-clock time reflects it.
All duration calculations run locally. Dates and times never leave your browser.
How to Use This Tool
Choose Duration Between or Add / Subtract Time.
Select a time zone and enter the relevant date-times or elapsed units.
Calculate to see the exact duration or resulting local time.
Frequently Asked Questions
Elapsed-time results use real instants. A local calendar day can contain 23 or 25 hours when daylight saving time changes.
Yes. The tool reports the absolute duration and clearly states that the ending time is earlier.
It adds exact elapsed hours, minutes, and seconds, then formats the result in the selected zone using the applicable offset.
No. Everything is calculated locally in your browser.
Before You Use This Tool
A quick overview of what this page is good for, how it handles data, and what to expect before you start.
What It Does
- Measure elapsed time or add and subtract hours, minutes, and seconds with DST-aware results in your browser
Access & Privacy
You can use the main workflow without creating an account.
The main workflow runs in your browser, so files stay on this device during processing.
Good Fit For
- Solve one-off browser tasks quickly.
- Get useful output without installing anything first.
- Handle small jobs directly on the page and move on.
For repeated bulk jobs or advanced automation, dedicated desktop software may still be faster.