Chronometer
A stopwatch with lap times, accurate to the millisecond.
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About the chronometer
A stopwatch with lap timing, accurate to the centisecond and driven by the browser's monotonic performance clock rather than wall time. Space starts and pauses, L records a lap, R resets, and lap splits can be copied in one click.
Frequently asked questions
Is it accurate enough for benchmarking?
For anything measured by hand, yes — human reaction time swamps the timer's error. For code, use performance.now() in the code itself, since a hand-driven start adds a tenth of a second of noise.
Does it keep time if I switch tabs?
Yes. Elapsed time is calculated from timestamps rather than counted frames, so the reading stays correct even though background tabs stop repainting.