Online Stopwatch
Start, stop and reset a stopwatch with hundredths of a second. It runs in your browser tab.
Quick answer. Press Start to begin timing, Stop to pause, and Reset to clear. The display shows hours, minutes, seconds and hundredths.
How it works
The stopwatch reads the browser clock and shows elapsed time in hours, minutes, seconds and hundredths of a second.
Elapsed time is calculated from the start time, so it stays accurate when you return to a tab that was in the background.
Limits
This is suitable for everyday timing. Official sport or laboratory timing needs certified equipment.
Starting and stopping
Press Start when the activity begins and Stop when it ends. Press Reset to clear the display before the next timing.
The display shows hours, minutes, seconds and hundredths of a second, so short intervals are readable.
Accuracy and limits
The stopwatch uses the browser clock and reads time with high resolution. Your device, browser load and background activity can add small delays to the displayed value.
Questions
Does it keep running if I switch tabs?
Yes. The elapsed time is calculated from the start time, so it stays accurate.
Is it accurate enough for sport timing?
It is suitable for everyday timing. Official timing needs certified equipment.
Does the stopwatch continue after I close the tab?
No. Closing or reloading the page stops and clears the stopwatch.
Last updated: 2026-10-08. Uses the browser's high resolution clock. Timing method checked against the browser clock.