Stopwatch: Precise Time Measurement with Lap Recording

Need to time something precisely? Our free online Stopwatch uses requestAnimationFrame for smooth, accurate timing down to centiseconds. Record lap times, see your best and worst laps highlighted, and copy results to your clipboard.

How to Use the Stopwatch

1. Start: Click the Start button to begin timing
2. Lap: While running, click Lap to record a split time without stopping the clock
3. Stop: Click Stop to pause the stopwatch. Click Resume to continue from where you left off
4. Reset: Click Reset to clear the time and all recorded laps
5. Copy: Click the Copy button above the lap table to copy all lap data to your clipboard

Features

• Centisecond precision: Displays time as HH:MM:SS.cc with smooth updates
• Lap recording: Record unlimited lap/split times while the stopwatch runs
• Best and worst laps: When you have two or more laps, the fastest is highlighted in green and the slowest in red
• Clipboard export: Copy all laps as tab-separated text (lap number, split time, total time) for pasting into spreadsheets
• Smooth rendering: Uses requestAnimationFrame instead of setInterval for accurate, jitter-free display

Common Use Cases

• Running and athletics: Time laps around a track or intervals during training
• Cooking: Measure how long a step takes when developing recipes
• Presentations: Track how long each section of a talk takes during rehearsal
• Games and competitions: Time rounds, turns, or challenges
• Debugging: Measure how long a manual process takes to complete
• Science experiments: Record timing data for observations

Understanding the Lap Table

Each lap entry shows two values:

Column	Meaning
Lap	Time for just that lap (since the previous lap or start)
Total	Cumulative time from when the stopwatch started

The most recent lap appears at the top of the table. With two or more laps recorded, the fastest lap time is shown in green and the slowest in red, making it easy to spot your performance range.

Tips

• The stopwatch continues running even if you scroll down, as long as the tab is open
• Use the Copy button to export laps into a spreadsheet for analysis
• The display updates at your screen’s refresh rate (typically 60fps) for smooth reading
• Clicking Stop doesn’t erase your time. You can resume or record the final elapsed time

Frequently Asked Questions

How accurate is the stopwatch? It uses performance.now() and requestAnimationFrame, which provide sub-millisecond precision in modern browsers. Display shows centiseconds (hundredths of a second).

Can I record laps while the stopwatch is stopped? No. The Lap button is only available while the stopwatch is running.

Does it work on mobile? Yes. The stopwatch works on any modern browser, including mobile devices.

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Try our free Stopwatch to time anything with lap recording.