Online Stopwatch
This free online stopwatch measures elapsed time with a big, easy-to-read display accurate to one hundredth of a second (10 ms).
00:00.00
How to use
- Press Start — the big display begins counting up immediately, to a hundredth of a second.
- Press Lap whenever you want to record a split; laps are listed below with each segment's duration.
- Press Pause to stop measuring and Start to resume from the same point.
- Press Reset to return to 00:00.00 and clear the lap list when you are done.
Frequently asked questions
How accurate is this stopwatch?
The display shows hundredths of a second (10 ms), and elapsed time is computed from your device clock at every refresh, so there is no cumulative drift from animation timers. Human reaction time when pressing the button (typically 100–300 ms) is the practical limit.
What is a lap or split time?
A lap records the moment you press the button without stopping the clock. The list shows the total elapsed time at that moment plus the duration of the segment since the previous lap, so you can compare each section.
Does it keep running if I switch tabs?
Yes. The stopwatch is anchored to your device clock, so background tab throttling does not affect the measured time; the display catches up instantly when you return.
Can I measure more than an hour?
Yes. The display switches to an hours:minutes:seconds.hundredths format automatically after one hour.
Is anything uploaded or stored?
No. Timing happens entirely in your browser and is not stored anywhere — reloading the page resets everything by design.
Related tools
About this tool
This free online stopwatch measures elapsed time with a big, easy-to-read display accurate to one hundredth of a second (10 ms). Press start and the clock runs; press pause to freeze it and start again to resume from the same moment; press lap to record split times without stopping the clock, and reset to return to zero and clear the laps. The lap list shows the total elapsed time at each press plus the duration of each individual segment, so you can analyse pacing in workouts, experiments, cooking steps, presentations or any recurring task. Under the hood the stopwatch is anchored to your device's own clock rather than a counting loop, so it stays accurate even if the tab is throttled in the background. It runs entirely in your browser: nothing to install, nothing to sign up for, and no data leaves your device.