Countdown Timer
Set a countdown with alarm — full-screen friendly, works offline.
Free · No sign-up · Runs locally in your browser · Also available in Chinese (中文)
What is Countdown Timer?
A countdown timer counts down from a set duration and alerts you at zero — for cooking, workouts, meetings and classroom activities. It computes the end timestamp at start and checks remaining time against the monotonic clock, so sleeping the display does not silently extend your countdown.
The alarm is a browser notification plus an in-page sound, and a large-digits display makes the remaining time readable across the room. Because it is a web page, it works on any device around the house or office without installing an app.
How to use it
- 1Set hours, minutes and seconds (quick buttons for common durations).
- 2Press start; pause and resume are supported.
- 3At zero the page alerts — dismiss it to stop the sound.
- 4Reset to set a new duration.
Common use cases
- Kitchen and workout timing on a tablet propped on the counter.
- Timeboxed meeting segments and presentation rehearsals.
- Pomodoro-style focus blocks with a visible large countdown.
Frequently asked questions
▸Will the alarm sound if the tab is in the background?
Yes — the check runs on the monotonic clock even when the tab is hidden. Allow notifications if you want a system-level alert too.
▸What if my device sleeps?
On most systems the page keeps running; if the device fully suspends, reopen the tab and the remaining time recalculates from the real target timestamp.