Online Stopwatch

Start, record laps and stop. Keyboard: Space to start or stop, L for a lap, R to reset (when the stopwatch has focus).

Stopwatch

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    How it keeps accurate time

    The stopwatch records the moment you press Start using the browser’s high-resolution clock (performance.now()) and computes elapsed time from that reference on every screen refresh. It never counts ticks, so the time stays correct even if your browser slows down updates in a background tab.

    Laps and splits

    Each lap row shows the lap time (time since the previous lap) and the split (total time since the start). The fastest and slowest laps are marked once you have at least three.