Stopwatch & Timer
Online stopwatch with lap times and countdown timer with alarm.
Frequently Asked Questions
What keyboard shortcuts does the stopwatch support?
Space bar toggles start/stop for both the stopwatch and timer. R resets the current mode. L records a lap while the stopwatch is running. Shortcuts only fire when focus is not inside an input field, so you can type in the timer duration without accidentally resetting.
How does the countdown timer alarm work?
When the countdown reaches zero, the alarm uses the Web Audio API to generate three short 880 Hz sine-wave beeps synthesised directly in-browser — no audio file is downloaded. If your browser blocks audio until user interaction, click anywhere on the page first to enable sound.
Does the stopwatch keep running if I switch browser tabs?
Yes — the stopwatch uses JavaScript's performance.now() or Date.now() to track absolute elapsed time, so it continues accurately even when the tab is hidden or the browser is minimised. This is more reliable than timer-based approaches that can drift when tabs are throttled.
What is the best lap / worst lap highlighting?
After recording two or more laps, the fastest lap time is highlighted in green and the slowest in red — useful for tracking consistency in interval training, running, or any timed repetitive activity. The lap table also shows the cumulative split time alongside each individual lap.