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Stopwatch

Lap, split, and reset. Centisecond precision.

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00:00.00

About Stopwatch

A centisecond-precision stopwatch with lap recording and split-time tracking. Eight laps fit on the screen at once, sorted from newest to oldest. The digits use tabular-nums so the counter never jitters as the milliseconds tick past. Built for PE teachers, sports coaches, speedrunners, and anyone timing a process that needs sub-second accuracy.

Centisecond Precision

The stopwatch updates every frame (roughly 16ms on a 60Hz panel, 8ms on a 120Hz), but displays centiseconds (10ms) because that is the resolution the human eye can reliably read. Milliseconds would blur past too fast to register; centiseconds are the sweet spot for athletic timing, speedrun splits, and cooking precision.

Laps vs Splits

A lap records the time since the last lap button press. A split records the total elapsed time. This stopwatch records laps — tap the Lap button eight times and the screen fills with your eight most recent segment times, newest at the top. Useful for interval training, relay race practice, and tracking pacing across a long run.

How to use it

  1. 01

    Press Start

    The stopwatch begins counting from 00:00.00.

  2. 02

    Lap

    Press Lap to record a segment time. Up to eight laps display at once.

  3. 03

    Pause and Resume

    Press Pause to freeze the counter. Press Resume to continue from where you stopped.

  4. 04

    Reset

    Press Reset to clear the counter and all lap times.

Frequently asked

The shortest path between you and the answer.

Is this accurate enough for sports?

For training and recreational timing, yes. For sanctioned athletic events, a certified timing system is required. Browser timers are subject to the OS scheduler and cannot guarantee sub-millisecond precision.

Is this tool free?

Yes. Every ScreenTools.co tool is free, with no account, no paywall, and no install.

Does it work on mobile?

Yes. Layouts adapt to phone and tablet screens. Mobile Safari restricts true fullscreen, but the page fills the viewport and you can add the page to your Home Screen for an app-like experience.

Does it work offline?

Once a tool's page has loaded once, the runtime is local. A few tools that fetch fonts or icons need the first hit online; after that, refresh works offline.

Does this collect my data?

No personal data leaves your browser. The site has lightweight, privacy-respecting analytics for aggregate counts (which tool was opened) and nothing else.

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