Stopwatch & Timer
Millisecond-precise stopwatch with lap tracking, plus a countdown timer with an audio alert. Keeps running when the tab is in the background.
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How to Use the Stopwatch & Timer
Click Start to begin the stopwatch. Click Lap while running to record split times — the fastest lap is highlighted green and the slowest amber. Click Pause then Reset to clear. Switch to Countdown mode and set a duration using presets or by clicking the display to edit hours, minutes, and seconds. The timer plays an audio alert when complete and works accurately even when the browser tab is in the background. Use keyboard shortcuts: Space to start/pause, L to lap, R to reset.
About This Tool
A precision stopwatch and countdown timer built entirely with web platform APIs. The stopwatch uses performance.now() for drift-free millisecond timing that stays accurate even when the browser tab is backgrounded. The countdown timer features a circular progress ring, preset durations for quick setup, an audio alert generated via the Web Audio API (no audio files), optional browser notifications, and repeat mode for interval training or Pomodoro sessions. Run up to four independent timers simultaneously. Zero external libraries — the entire tool works offline after the initial page load. Pair with the Reading Time Estimator for content timing or the Date Calculator for date arithmetic.
Frequently Asked Questions
Does the timer work when I switch tabs?
Yes. The timer uses the browser’s performance clock as its time source, not the animation frame count. When you switch tabs, the animation pauses to save CPU, but the underlying clock keeps running. When you switch back, the display immediately shows the correct time.
Why does my countdown not beep when the tab is in the background?
Browsers restrict audio playback to active tabs. Enable the browser notification option in settings — this uses the Notifications API to alert you even when the tab is backgrounded or minimized.
How many timers can I run at once?
You can run one stopwatch and up to three countdown timers simultaneously — four timing functions in total. Each runs independently with its own start, pause, and reset controls.
How precise is the stopwatch?
The stopwatch displays milliseconds and uses performance.now() as its time source, which has sub-millisecond resolution on modern browsers. The practical precision is around 1–5 milliseconds, which is more than sufficient for sports timing, cooking, and productivity.
Can I set a timer for more than an hour?
Yes — the maximum duration is 99 hours, 59 minutes, and 59 seconds. Click the hours segment of the display and type the desired value.
Created by The Toobits Team · Engineering & Editorial
Toobits is built, tested, and maintained by a small independent engineering team. Every tool is written in TypeScript, runs entirely in the browser, and is reviewed against its source formulas before publication.
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