Stopwatch & Timer
Two timing tools in one: a stopwatch that counts up and a countdown timer that counts down, switchable via tabs. The stopwatch shows hours, minutes, seconds, and hundredths, with start, stop, reset, and lap buttons. Laps are listed in reverse chronological order so the most recent is always on top.
The countdown timer lets you set hours, minutes, and seconds, then counts down with a progress bar. When time runs out, the display flashes and shows a clear alert. You can pause and resume at any time — the remaining time picks up exactly where it left off.
Both modes use wall-clock timestamps (Date.now()) rather than interval-based counting, so they stay accurate even when the browser tab is in the background or the system throttles timers. The display updates via requestAnimationFrame for smooth, jank-free rendering when the tab is visible.
By The Paper Room Editorial Team — Misc Utilities
Frequently asked questions
Does the stopwatch keep running if I switch tabs?▼
Yes. The stopwatch tracks elapsed time using wall-clock timestamps, not by counting intervals. When you return to the tab, the displayed time will be accurate regardless of how long you were away.
How accurate is the timing?▼
Accuracy depends on your browser's Date.now() resolution, which is typically within a few milliseconds. For casual timing that is more than sufficient. For scientific or competition timing, dedicated hardware is recommended.
What happens when the countdown timer reaches zero?▼
The display flashes red and shows a 'Time is up!' message. The timer does not loop or restart automatically — press Reset to set a new duration.
Can I use the stopwatch and timer at the same time?▼
They operate independently, but only one is visible at a time via the tabs. Switching tabs does not reset or pause the other — both keep tracking in the background.