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TabBench

Online Stopwatch

Digital millisecond stopwatch with split and lap delta tracking, plus countdown timer with presets, synthesized chime alarms, and fullscreen mode.

Runs in your browser. Nothing you add is uploaded.

What the Online Stopwatch does

Whether you are timing sprints, measuring workout intervals, tracking productivity with Pomodoro sprints, or steeping tea, having a responsive, accurate timer is essential. This browser utility combines a precision millisecond digital stopwatch with a flexible countdown timer. The stopwatch includes lap recording with split times, lap deltas, and automated fastest/slowest lap highlighting. The countdown timer features an intuitive circular progress ring, one-click duration presets, fullscreen mode, and a synthesized melodic chime that alerts you when time expires.

How to use the digital stopwatch and countdown timer

  1. Switch between 'Digital Stopwatch' and 'Countdown Timer' using the top category selector.
  2. For the Stopwatch: Click 'Start' to begin timing. Click 'Lap' to record intermediate split times. Fastest laps are badged in green and slowest in amber.
  3. For the Timer: Select a quick preset (e.g., 5m, 10m, 25m Pomodoro) or enter your custom duration, then click 'Start'.
  4. When the countdown timer finishes, an audio alarm plays automatically with a visual alert.
  5. Click the Fullscreen icon to expand the timer for presentations, gym workouts, or kitchen cooking displays.

The Online Stopwatch runs entirely in your browser — nothing you enter is uploaded, stored, or logged.

When to use it

Athletic training & track split timing

Measure lap times and analyze pacing improvements with centisecond precision and automated lap comparison.

Pomodoro study & deep work sessions

Boost productivity by working in uninterrupted 25-minute sprints followed by 5-minute cooldown periods.

Presentations & public speaking

Launch fullscreen mode on a podium or second screen to stay strictly within allotted presentation speaking times.

Good to know

  • Use 'Copy Laps' on the stopwatch to paste a cleanly formatted log of all lap and split times into your notes or spreadsheet.
  • The timer continues tracking elapsed time accurately even if you switch browser tabs.

Frequently asked questions

How accurate is this online stopwatch?

The stopwatch tracks real elapsed wall-clock time using high-resolution browser timestamps, providing reliable 10-millisecond (centisecond) precision even if background tabs experience minor throttling.

Does the countdown timer play a sound when it reaches zero?

Yes! When the countdown timer completes, a melodic audio chime plays automatically. You can toggle audio on or off anytime using the sound control icon in the header.

Can I export or copy my lap times?

Yes, click 'Copy Laps' to copy a formatted list of all split and individual lap times directly to your clipboard for spreadsheets or workout logs.

Does the timer sound require downloading MP3 files?

No. The audio chime is synthesized entirely inside your browser via the Web Audio API, ensuring instantaneous playback with zero network dependency.

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