How it works
The countdown updates once per second in your browser, using your device's clock and local timezone. It always reflects the time difference between the target you set and the current moment — there's nothing to refresh.
time remaining = target date/time − current date/time, refreshed every second
Worked example
Because this calculator is always counting down live, there's no single fixed answer to show — but here's a snapshot: set a target for midnight on New Year's Eve, and with 8 hours left to go, the display would read 0d 08h 00m 00s and keep counting down from there, second by second, until it reaches zero and switches to "Already passed."
Common questions
Does the countdown keep running if I leave the tab open?
Yes — as long as the page stays open, it ticks down every second automatically. No need to refresh the page or re-enter the date.
What timezone is the target time in?
Your browser's local timezone — whatever your device is currently set to. If you share a link to this page with someone in a different timezone, they'll need to re-enter the target time in their own local time to get the same countdown.