How to use it
Press Start to measure elapsed time. Use Lap to mark a split while the stopwatch is running. Pause and resume without losing the accumulated time. Reset clears elapsed time and all laps. The display shows hundredths of a second, subject to browser scheduling and clock precision.
Try this example
If the first lap is recorded at 12 seconds and the next at 27 seconds, the lap times are 12 and 15 seconds. Total elapsed time is 27 seconds. Pausing for ten seconds does not add those seconds to the stopwatch.
What to know
Only settings and sound preference are saved on this device. Reloading, closing this page or navigating to another tool ends the active session and clears laps. Keep the page open for timing. Fullscreen requires browser support; Escape exits it. No notification permission is requested.
Frequently asked questions
What is the difference between lap time and total time?
Lap time is the elapsed duration since the previous lap. Total time is the accumulated running time since Start. Up to 500 laps can be recorded in one session.
Keep this page open. Browser throttling, device sleep or muted audio can delay alerts. This is not a safety-critical alarm.