How to use the Online Stopwatch & Countdown Timer
- Choose Stopwatch or Countdown.
- Start, pause, lap or reset.
- Listen for the alert when the countdown ends.
How it works
The stopwatch measures elapsed time with the browser’s high-resolution clock and shows tenths of a second. The countdown subtracts from a target end time, so it stays accurate even if the tab is briefly busy.
Worked example
A 5-minute countdown beeps at zero; a stopwatch with two laps shows each split and the total.
Good to know
Keep the tab open for the timer to alert you.
Lap times show the split since the previous lap.
Browsers may block sound until you interact with the page.
Frequently asked questions
Press Lap while the stopwatch runs.
It usually does, but background tabs can be throttled; keep it visible for reliability.
Accurate to roughly a tenth of a second for everyday use.