Stopwatch

Laps, and what the two columns mean

Press Lap and the row that appears shows two times: the split, which is how long that lap took, and the total since you started. Newest at the top, so the one you just took is where your eye already is.

Stop pauses without clearing anything, so you can stop, read the laps and start again from where you were. Reset is the only thing that clears them, and it needs a deliberate press.

About the last digit

The display shows hundredths of a second because that is what people expect from a stopwatch, and the time itself is read from your computer's clock, so it does not drift. But the last digit depends on the browser: pages are repainted about sixty times a second at best, and browsers deliberately blur their timing a little for security reasons.

So treat the hundredths as an honest reading rather than a precise measurement. For timing a lap in a pool or a race that matters, a real stopwatch — or a phone's own — is the right tool. And your reaction time at the button is almost certainly larger than any error here.

What happens when you look away

The clock keeps running in a hidden tab, even though the display stops repainting: come back and the time is right. While it runs the page asks to keep the screen awake, and releases that the moment you stop, hide the tab or leave — and if your browser refuses, the page says so rather than letting you assume.

Nothing is stored. Leaving the page discards the time and every lap: there is no history and no export, because this site keeps nothing between visits.

For counting down instead of up, use the Countdown Timer or the Pomodoro Timer; for the time of day, the Fullscreen Clock.