Countdown timer
Run a simple countdown with pause, resume and an optional sound.
Up to 99 hours, 59 minutes and 59 seconds. Keep this page open. Background tabs may delay the sound; the display catches up when you return. Reloading clears the timer.
Everything runs in your browser. Your entries are not uploaded or saved.
How it works
Set hours, minutes and seconds, then press Start. Pause freezes the remaining duration; Resume continues from there. Reset returns to the entered duration. The example loads a one-minute countdown without starting it.
Good to know
Will the timer work if I leave the page?
The countdown uses a deadline rather than counting browser callbacks, so a delayed tab updates to the correct remaining time. Keep the page open: closing or reloading loses the timer, and sleep or background restrictions may delay alerts. Sound is optional and may be blocked; the visible completion message remains available.