Birthday countdown

Enter your date of birth and the page counts down to your next birthday. If today is your birthday, the page shows a celebration message for the whole day instead of counting backwards.

How the math works

If your birthday is February 29 (a leap-year baby), the page targets February 28 in non-leap years so you get a count every year. Time zones don't change which day your birthday falls on; the count is anchored to your device's local midnight on the relevant date. Your date of birth is saved only in this browser, never sent to our servers.

Common questions

What time zone does the countdown use?

Your device's local time. Midnight on New Year's Eve in Tokyo is not midnight in London; the page counts down to whichever midnight is yours.

Does the countdown keep running if I switch tabs?

Yes. The page reads the current time on each tick; an inactive tab catches up the moment you return.

What happens when it hits zero?

A short celebration message appears on the page. There is no popup or alarm sound by default, so the page can sit on a second monitor without surprising anyone.

Can I make the digits bigger?

Yes. The size buttons (S, M, L, XL, 2XL, 3XL) live in the settings panel and the choice saves for next time. Use fullscreen for a wall display.

Does it work on my phone?

Yes. The layout collapses to a two-column grid on phones so three-digit day counts still fit.

Tips

Save the page to your home screen and the countdown becomes a one-tap glance without browser chrome around it. Pin the tab in your desktop browser so you can leave it running for weeks without it getting closed by accident. Theme effects (the confetti or pumpkin background on the seasonal pages) can be turned off in the settings if a moving background is distracting.