Stopwatch Tool

Online Stopwatch - Precise, Free Millisecond Timer With Lap Tracking

Time anything with millisecond accuracy and unlimited lap tracking. No sign-up or software download required.

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How to Use the Stopwatch

1. Start Timing: Click Start to begin. The ring and digits update live to the millisecond.
2. Record a Lap: While the stopwatch is running, click Lap to capture a split. You can record unlimited laps in a single session.
3. Pause or Resume: Click the same button again (now labeled Pause or Resume) to stop or continue without losing your time.
4. Reset: Click Reset to clear the time and all recorded laps and start a fresh session.

Why Precise Timing Matters

Accurate timing is essential for sports training, fitness intervals, cooking, study sessions, and lab work, where small measurement errors compound over repeated intervals.

This stopwatch runs entirely in your browser using requestAnimationFrame for smooth, millisecond-accurate updates, and no timing data ever leaves your device.

Timing Reference

Quick reference for how the stopwatch's lap statistics are calculated:

Precision: 1/1000 second (millisecond)

Lap Split: Elapsed minus sum of previous laps

Best Lap: Fastest recorded split

Average Lap: Sum of splits ÷ number of laps

Frequently Asked Questions

This stopwatch uses JavaScript's requestAnimationFrame for smooth updates and displays time with millisecond precision (1/1000 of a second). The accuracy depends on your device's system clock, which is typically accurate to within a few milliseconds.

While the stopwatch is running, click the Lap button. Each lap time is recorded and displayed in the list below, along with total elapsed time. You can record unlimited lap times during a single timing session.

Best Lap shows your fastest recorded lap time. Average Lap calculates the mean time of all recorded laps, helping you identify consistency in your performance across multiple intervals.

This stopwatch is suitable for sports training, fitness tracking, cooking, and general purpose timing. For official competitive events or scientific experiments requiring certified accuracy, please use professional calibrated equipment.

No, timing stops when you close the browser tab or refresh the page. This is a security feature of web browsers. For extended timing sessions, keep the tab open and active.

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All timing runs locally in your browser. Closing or refreshing the tab resets the stopwatch and lap data.