● runs entirely in your browser Start, stop, and record laps.
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How it works
The clock is driven by real timestamps rather than a counted interval: each Start records Date.now(), each Stop adds the elapsed difference into a running total, and the on-screen display is refreshed every animation frame via requestAnimationFrame. Lap just reads the current running total at that instant without stopping anything.
FAQ
How accurate is the timer if I switch to another browser tab?
The underlying time stays accurate because it's based on real timestamps, not a counted interval — but the visible display may stop updating in a backgrounded tab, since requestAnimationFrame only fires on visible tabs, and it catches up the instant you switch back.
Are lap times splits between laps, or running totals?
Running totals — each lap shown is the total elapsed time at the moment you clicked Lap, not the time since the previous lap.
Free, unlimited, no account. If this saved you a paid tool, a small thanks is appreciated.