Stopwatch

How it works

The stopwatch tracks the timestamp when you press Start and uses requestAnimationFrame for sub-millisecond display refresh. Pausing freezes the elapsed time and stores it; resuming continues from there. Tab visibility changes do not affect accuracy — the elapsed value is computed from real time, not interval ticks.

Frequently asked

Does the stopwatch keep running if I switch tabs?

Yes. We use the actual elapsed time between Start and now, so even if your browser pauses the rendering loop in a background tab, the time stays accurate when you switch back.

Are there keyboard shortcuts?

Yes — Space starts and pauses, L records a lap, R resets. Click anywhere on the page first to give it focus.

How accurate is it?

Display refreshes about 60 times per second. The underlying time value is whatever performance.now() reports — typically accurate to 0.1 ms in modern browsers, though browsers reduce that precision in some contexts to mitigate timing attacks.