Countdown Timer

Pick the date, add a title and press Copy link, then paste the link into WhatsApp, an email or anywhere else. The date and title are inside the link itself, after the # sign, so nothing is stored on a server, and each person sees the countdown in their own time zone.

Yes. The time left is worked out from the clock every time the screen is drawn, not counted down second by second, so it is right again the moment you come back. Browsers slow down tabs in the background, so the beep may come a few seconds late while the tab is hidden.

Yes. Press Full screen and the numbers fill the screen in large type, readable from the back of a classroom. Press Esc or Exit full screen to come back.

Browsers only play sound after you have tapped or clicked on the page, so press Start, or tap the page once after opening a shared link. Check that Beep at zero is ticked and the device isn't on silent. Phones that can vibrate also vibrate.

No. The countdown runs in your browser and nothing you type is sent anywhere. The date and title leave your device only inside a link you choose to copy and share.