Online stopwatch

How to use

1. Press Start to begin timing, Pause to stop it and Resume to continue. Reset returns the time to zero and clears the laps.
2. While the stopwatch is running, press Lap to record the total time at that moment. Each lap time is the difference from the previous lap. Once there are three laps, the fastest and slowest laps are marked.
3. The elapsed time is calculated as the current time minus the start time, so it remains correct after you switch tabs or your computer goes to sleep. The display shows hundredths of a second, and the lap list shows thousandths.
4. The start time and the laps are stored in this browser, so they remain after you reload or close the page.
5. Keyboard shortcuts: Space starts, pauses or resumes, L records a lap, and R resets.
6. This tool runs in your browser. What you enter and your timing records are stored only in this browser and are not uploaded.

Common questions

How accurate is this stopwatch?

It uses the browser’s high-resolution clock, which is accurate to within a thousandth of a second. The screen refreshes about 60 times a second, so the display shows hundredths. In practice, most of the error comes from your reaction time.

Does the stopwatch keep running after I close the page?

Yes. The start time is stored in this browser, so the stopwatch continues from the elapsed time when you open the page again.

What is the longest time it can show?

The display goes up to 99 hours 59 minutes 59.99 seconds. Please reset it after that.