Countdown Timer
Pick a future date and time and watch the countdown run live, down to the second. The link updates as you type, so you can copy it and send it to anyone — opening it shows the same countdown, running live from that moment.
⏳ This moment has passed. Pick a future date and time to start a new countdown.
A live countdown that can't drift, and a link that remembers it
Every second, a setInterval tick recomputes the gap
between your target date and the actual current time from
scratch — target − now, in milliseconds — and
splits the remainder into whole days, hours, minutes, and
seconds. Recalculating from the real clock each tick, instead of
just decrementing a running counter, means the display can never
drift out of sync even if the tab sits in the background or the
computer briefly sleeps. If the target moment is already in the
past, the four numbers are replaced with a plain "This moment
has passed" message rather than a confusing negative countdown.
The target date and time are also written into the page's own
URL as a ?target= parameter the moment you pick
them, using a timezone-independent ISO timestamp. That makes the
countdown fully shareable: copy the link (or use the "Copy
link" button) and send it to anyone — when they open it, the
same countdown starts running immediately, calculated fresh
against their own clock, pointing at the exact same absolute
moment in time.
Frequently asked questions
What happens when the countdown reaches zero?
Once the target moment passes, the four numbers disappear and the tool shows "This moment has passed" instead of counting into negative numbers or showing NaN. It keeps checking every second, so if you correct the date to a future one, the live countdown starts again immediately.
Can I share a countdown with someone else?
Yes — as soon as you pick a date and time, the page updates its own URL with that target baked in (as a ?target= parameter). Copy the address bar, or use the "Copy link" button, and anyone who opens that link sees the same countdown running live from the moment they open it.
What time zone is the countdown in?
The date and time you pick are read in your device's local time zone, and the countdown runs against your device's current local clock — so if you share a link with someone in a different time zone, the target moment is still the same absolute instant, but they'll see it labeled with their own local time when they open the picker.
Does the timer keep running if I leave the tab open overnight?
Yes — it recalculates the remaining time from scratch every second using the actual system clock, rather than just subtracting one second at a time, so it can't drift out of sync even if the tab is left open, backgrounded, or the computer sleeps briefly.