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About this tool
Run multiple named countdown timers with progress rings, alarms, and presets — accurate even in background tabs.
Countdown Timer is a multi-timer countdown that runs any number of named timers at once, each with its own progress ring, and keeps accurate time in background tabs because it counts down to an absolute end timestamp rather than by ticking. Durations run from one second up to 99 hours 59 minutes 59 seconds, with one-tap presets at 1, 3, 5, 10, 15, 30 and 60 minutes, and every timer is saved to local storage so a reload or accidental tab close does not lose it. When a timer ends it plays a triple 880 Hz beep and flashes "Time's up!" in the browser tab title.
Open Countdown Timer on AltFTool — it loads instantly in your browser.
Name the countdown in the Timer name box (up to 40 characters), set the Hours, Min and Sec fields or tap a Quick preset — 1, 3, 5, 10, 15, 30 or 60 min — then press Add timer; the button stays disabled until the duration is above zero.
Press Start on the timer card to begin. The ring drains as the time runs down, the card reads Counting down, and its subtitle switches from Total to the clock time it Ends; Pause holds it and the button becomes Resume, while Reset returns the card to its full duration.
At zero the card turns red, shows Time's up! with a triple beep, and the browser tab flashes ⏰ Time's up! — press Dismiss to clear the alert, Restart to run it again, or the trash button to delete the timer. Timers are stored in your browser, so reloading the page keeps a running countdown on track.
Each running timer stores its end time, so browser throttling of inactive tabs cannot make it drift or stall.
Every timer has its own label, ring and controls, so overlapping countdowns never get confused for one another.
Timers persist in local storage, and one that expired while the page was closed comes back already marked done.
Yes. It counts down to a fixed end timestamp instead of decrementing a counter, so even when the browser throttles the inactive tab's timers the remaining time is recalculated correctly the moment you return, and an expired timer is marked done.
99 hours, 59 minutes and 59 seconds — just over four days. Hours accept 0-99 and minutes and seconds accept 0-59, and presets are available at 1, 3, 5, 10, 15, 30 and 60 minutes.
It plays three short 880 Hz beeps through the Web Audio API and the browser tab title flashes "Time's up!" once a second until you acknowledge the timer. Your device must not be muted, and the sound only works after you have interacted with the page, since browsers block audio until then.
Yes, in your browser's local storage under a single key — nothing is sent to a server. Reopening the page restores every timer with its name and duration; anything that was running and has since passed its end time reappears in the done state. Clearing site data or using a private window will lose them.