UtilTools

Stopwatch

Start, stop and lap times to the hundredth.

Stopwatch measures elapsed time to hundredths of a second with lap recording, showing each lap and the cumulative split. Timing is based on a monotonic performance clock, so it is unaffected by a system clock change, and laps can be exported as CSV.

Loading Stopwatch…

Runs entirely on your device. No file or text you enter here is uploaded. How to verify it.

How to use Stopwatch

  1. Press start.
  2. Record laps as you go.
  3. Stop, review the splits, and export if you need them.

Questions about Stopwatch

How accurate is it?
It uses performance.now(), a monotonic high-resolution clock, so the elapsed measurement is precise to well under a millisecond even though it is displayed to hundredths. Display refresh, not measurement, is the limiting factor.
What is the difference between a lap and a split?
A lap is the time since the previous lap mark; a split is the total elapsed at that mark. Both are shown for every lap, because coaches and runners mean different things by the word.
Does it survive a page reload?
A running stopwatch is restored from its start timestamp, so a reload does not lose your elapsed time — though it does clear the laps.
Can I get the lap times into a spreadsheet?
Yes. The export writes a CSV with one row per lap, holding the lap number, the lap time and the cumulative split, and it opens directly in any spreadsheet application. The file is generated in the page and saved straight to your device.
Does it keep counting if I switch tabs on a phone?
The elapsed time stays correct, because it is derived from the start timestamp rather than from a counter that ticks. The display may stop refreshing while the tab is in the background, but it catches up the moment you come back to it.
Is Stopwatch really free, with no limits?
Yes. There is no account, no daily cap, no file-size tier and no watermark, because there is no server cost to recover. The site is funded by clearly disclosed partner recommendations on the Partners page, never by metering the tools.
Are my files or text uploaded when I use Stopwatch?
No. Everything is processed by JavaScript running in your browser, on your device. You can verify it: open your browser's developer tools, switch to the Network tab, and use the tool. You will see no request carrying your data — because there is nowhere for it to go.