Stopwatch

A simple online stopwatch with lap splits, accurate to a hundredth of a second. Start, stop and record laps; runs entirely in your browser, even offline.

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Laps

No laps recorded yet.

How it works

The stopwatch measures elapsed time from start and stop timestamps on your device's clock rather than by counting screen updates, so a busy or hidden page, or a screen that goes to sleep, doesn't make it drift. Press Lap to record a split without stopping; each lap shows both its own time and the cumulative total.

Nothing is sent anywhere and no times are saved between visits, the stopwatch runs entirely in your browser.

What this does

An online stopwatch measures elapsed time to a hundredth of a second, with lap splits you can record on the fly.

How to use it

  1. Press Start to begin timing.
  2. Press Lap to record a split.
  3. Press Stop to pause.
  4. Reset to clear and start again.

Understanding your result

Elapsed time is read from your device’s clock rather than counted tick by tick, so the total stays accurate even if the tab is backgrounded or the screen sleeps. Each lap shows both its own split and the running total at that point, so the laps always add up to the overall time. Treat it as good to a few milliseconds, reliable for workouts and cooking, not for lab-grade timing.

Example

Press Lap during a run and each split shows both its own duration and the running total at that point.

Last updated .

Frequently asked questions

Does it keep accurate time in a background tab?

Yes. It measures elapsed time against your device’s clock rather than counting ticks, so the total stays accurate even if the tab is inactive or the screen sleeps. Changing the device’s clock while it runs shifts the total.

What does the Lap button do?

It records a split without stopping the clock. Each lap shows both its own duration and the running total at that point.

Is my data stored?

No. The stopwatch runs locally in your browser and nothing is saved between visits.