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Stopwatch
A simple, precise stopwatch with lap timing and millisecond accuracy. Everything runs locally in your browser — no data leaves your device.
Features
- Millisecond precision — displays hundredths of a second (
MM:SS.cc) - Lap times — record split times while the stopwatch keeps running
- Keyboard shortcuts — control without touching the mouse
- No persistence — state resets on page reload (by design)
Keyboard Shortcuts
| Key | Action |
|---|---|
Space |
Start / Stop |
L |
Lap (while running) |
R |
Reset (when stopped) |
Esc |
Reset |
How It Works
The stopwatch uses performance.now() for high-resolution timing, avoiding drift from setInterval. The display updates at ~60 fps via requestAnimationFrame for smooth visual feedback.
Lap times are stored in memory only and shown in a scrollable list with the lap number, lap time, and total time at that point.
Use Cases
- Timing workouts, intervals, or sprints
- Measuring code execution or page load times
- Cooking multiple items with different start times
- Any situation where you need precise elapsed time tracking
Related Tools
- Timer — countdown/count-up with multiple simultaneous timers and alarm
- Unix Time — convert between timestamps and human-readable dates
- Date Difference — calculate exact span between two dates