Stopwatch
Measure elapsed time with a monotonic browser clock, centisecond display, and lap capture.
How to use
- Press Start.
- Press Lap while timing to capture the current elapsed value.
- Pause/resume or reset when needed.
Capabilities and scope
A lightweight stopwatch supporting start, pause, resume, reset, and multiple lap timestamps.
How it works
Elapsed time is based on `performance.now()` and the display state is refreshed roughly every 31 ms. Pausing stores accumulated elapsed time so resuming continues from that base.
Example
Pressing Lap near 10 seconds preserves that cumulative timestamp in the lap list.
Useful for
- Time a simple task
- Record multiple checkpoints
- Compare approximate durations across repeated tests
Before you use it
- Browser scheduling and display refresh mean this is not a certified sports or laboratory timing instrument.
- Laps exist only in page memory and disappear on reload.
Frequently asked questions
Does centisecond display guarantee 0.01-second accuracy?
No. It is a display resolution; browser scheduling prevents an accuracy guarantee.
Are laps saved permanently?
No. They are kept only in the current page state.