Chronometer

Free online stopwatch and chronometer with lap tracking. Measure precise time intervals with split timing for sports, cooking, and testing.

About

How to Use

Examples

Start → Lap at 5s → Lap at 12s → Stop at 15s → shows 3 lap times

Use to time a for-loop execution: start before loop, stop after

Track API response times across multiple requests using laps

Best Practices

• Use requestAnimationFrame-based timing (this tool's default) for sub-frame accuracy
• For very precise measurements, combine with performance.now() in your code
• Clear old lap data before starting a new timing session
• Use the Copy Laps feature to record timing data for later analysis
• The timer continues running even when the browser tab is in the background (via accumulated time)

Common Mistakes

• Expecting millisecond precision from setInterval — this tool uses requestAnimationFrame for better accuracy
• Forgetting to reset before starting a new timing session
• Confusing lap time (time since last lap) with total elapsed time
• Not accounting for browser throttling when the tab is in the background
• Using the stopwatch for very long durations (hours) where drift may accumulate

FAQ

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