Stopwatch
Precise online stopwatch with lap times. Start, stop, and record splits, all in your browser.
How This Stopwatch Works
This stopwatch uses requestAnimationFrame and performance.now() — the highest-precision timing APIs available in a browser. It updates every frame (~60 times per second), giving you centisecond accuracy (hundredths of a second).
The lap feature records the elapsed time at the moment you press it, without pausing the main timer. You can record as many laps as you want, and they're displayed in reverse chronological order so the most recent lap is always at the top.
Everything runs in your browser's memory — there's no server, no account, and no data persistence. If you navigate away from the page, the timer resets. For permanent time tracking, export your laps with the Copy button before leaving.
Time Format Reference
| Display | Meaning | Example Use |
|---|---|---|
| 00:05.23 | 5 seconds, 23 centiseconds | Short sprints, reaction tests |
| 02:30.00 | 2 minutes, 30 seconds | Exercises, presentations |
| 15:00.00 | 15 minutes exactly | Pomodoro-style work blocks |
| 1:00:00.00 | 1 hour | Long tasks, study sessions |
What this means for you: The format is MM:SS.cs (minutes, seconds, centiseconds). Hours appear automatically when elapsed time exceeds 60 minutes.
Common Uses for a Stopwatch
Workout Timing
Time rest periods between sets, HIIT intervals, or total workout duration. Lap function tracks individual set times without stopping the clock.
Cooking
Time steeping, blanching, resting, and other short cooking intervals that don't need a full countdown timer — just a quick "how long has it been?"
Presentations & Speeches
Track how long your presentation runs. Use laps to mark section transitions so you can see which parts are running long.
Performance Testing
Time how long manual processes take — page loads, form completions, onboarding flows — to benchmark user experience improvements.
Stopwatch vs Timer: Which Do You Need?
Stopwatch (count up)
- Measuring how long something takes
- Recording lap splits for comparison
- Open-ended tasks with no set duration
Timer (count down)
- Fixed-duration tasks (cooking, exercise)
- Pomodoro work sessions (25 min blocks)
- When you need an alarm at the end
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How to use this tool
Click Start to begin timing
Press Lap to record split times while the timer runs
Click Pause to stop, then Copy Laps to export your times
Common uses
- Timing workout intervals and rest periods
- Recording presentation and speech durations
- Benchmarking task completion times
- Tracking cooking intervals and preparation steps
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