Set any duration — from a few seconds to just under 100 hours — using the hours, minutes, and seconds fields, or start from one of the one-click presets. This is the general-purpose version of the timer; if you have a specific use in mind, the pages linked below are pre-configured for it.

Most countdown timers count down a number in memory once per second. That works fine as long as the tab stays focused and the device stays awake — but browsers throttle background tabs, and phones lock their screens, both of which can quietly desynchronize a naive countdown from real time.

This timer instead calculates the exact clock time the countdown should reach zero the moment you press Start, and re-derives the remaining time from that stored target on every update — including right after the tab regains focus or the device wakes up. There's no counter to drift, because nothing is ever accumulated tick by tick.

Type a duration into the hours / minutes / seconds fields (they're disabled while the timer is running — press Reset first to change it), or click a preset. Once you're happy with a duration, Copy timer link generates a URL that opens directly to that exact countdown, ready for someone else to press Start themselves.