Stopwatch & Timer
Local — Runs in your browser; files and input stay on this deviceFree — Free to useRun a stopwatch with lap splits or set a countdown with an alarm. Time is displayed to hundredths of a second.
00:00.00
Runs in your browser; files and input stay on this device
About the stopwatch & timer
The stopwatch counts upward and records lap splits; the countdown accepts a duration in minutes and sounds an alarm at zero. Both use the browser’s performance clock and run locally. A browser may delay visible updates or the alarm while a tab is suspended in the background.
How to use Stopwatch & Countdown Timer
- 1In Stopwatch mode, start timing and add laps while it runs; stop to pause or reset to clear time and laps.
- 2In Timer mode, enter a duration in minutes and start the countdown.
- 3Pause and resume the countdown as needed; the page plays a short alert when it reaches zero.
Frequently asked questions
- What precision does the stopwatch display?
- It displays hundredths of a second and updates with requestAnimationFrame using performance.now. It is a browser timing aid, not certified measurement equipment.
- Are lap times split intervals or total elapsed times?
- Each lap records the total stopwatch time at the moment you select Lap. It does not calculate the difference from the previous lap.
- Can I enter seconds directly in the countdown?
- The field accepts minutes and can parse decimal values, so 0.5 represents 30 seconds. There is no separate seconds field.
- Does the timer continue after the page is closed or reloaded?
- No. Stopwatch time, laps, and countdown state exist only in the current page session.