How to use the stopwatch
- Start and stop: the green button, or the space bar.
- Lap: while running, the left button records a lap, or press L.
- Reset: when stopped, the left button clears the time and laps.
Laps are listed newest first. The fastest lap is green and the slowest is red once you have at least two.
Accuracy
The stopwatch reads your device’s high-resolution clock and shows hundredths of a second. It keeps accurate time when the tab is in the background. In practice, human reaction time of about a fifth of a second matters more than the clock.
Uses
Track running and swimming laps, time a speech, measure how long a task takes or run a quick race. For counting down instead, use the countdown timer.
Questions and answers
Does the stopwatch keep running if I switch tabs?
Yes. It calculates elapsed time from the clock, so it stays accurate in the background.
Can I use it full screen?
Yes. Tap the full-screen button for big digits.
Are my laps saved?
Laps stay on screen until you reset or leave the page.