Online Stopwatch
- Start: begin timing
- Pause: suspend timing
- Reset: clear time and laps
- Lap: record current time for split timing
About the Stopwatch
Supports start/pause, reset, and lap records. Display precision: centiseconds.
Uses requestAnimationFrame with performance time source for smooth updates. State persists to local storage and restores after reopen.
FAQ
Why not exact milliseconds?
Browser timers and rendering are bounded by system scheduling and refresh rate. We show centiseconds for stable, readable timing.
What happens in background tabs?
Frame rate is throttled. When returning, elapsed time is corrected using the time difference.
How are lap increments computed?
Each lap stores current elapsed time and shows the delta against the previous lap.
Cross-device or multi-window sync?
State is saved per browser window; multiple windows are not synchronized in real time.
Can it continue after refresh?
Yes. While running, start time is saved and restored so timing continues after reload.