Chronometer
A precise stopwatch with lap times. Uses requestAnimationFrame and performance.now() for accurate timing in the browser.
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Frequently Asked Questions
How accurate is this stopwatch?
The stopwatch uses requestAnimationFrame for display updates and performance.now() for time measurement, which provides sub-millisecond accuracy. Actual precision depends on your browser and system, but is typically within 1–5ms.
What are lap times vs split times?
A lap time is the duration of a single interval (from the previous lap or start). A split time is the total elapsed time from the start. Both are shown in the laps table for each recorded lap.
Does the stopwatch keep running in a background tab?
Yes. The elapsed time is calculated from absolute timestamps (performance.now), so even if the browser throttles animation frames in background tabs, the displayed time will be correct when you return.