Countdown Timer with Alarm
Free online countdown timer: set hours, minutes and seconds or count down to a date and time, with alarm sound, notifications and a progress bar.
The timer counts down to a fixed end time, so it stays accurate even when this tab is in the background.
What is Countdown Timer?
A countdown timer that runs in your browser. Count down a duration (for example 5 minutes or 1:30:00) or the time remaining until a specific date and time. When it reaches zero it plays an alarm and can show a desktop notification.
How to use Countdown Timer
- Choose Duration and enter hours, minutes and seconds, or click a preset such as 5 or 15 minutes.
- Or choose Until date & time and pick the target date and time (it is read in your own time zone).
- Click Start. Use Pause/Resume to hold the timer and Reset to start over.
- Keep Alarm sound checked to hear a beep at zero; tick Desktop notification to also get a system notification.
Example
Duration: 0 h 90 min 5 s
1:30:05
Minutes above 59 are converted automatically.
When to use Countdown Timer
Use it for cooking, breaks, exams, presentations or counting down to an event. Because it runs in a web page, it stops if you close the tab or the device sleeps completely; for alarms that must fire hours later on a phone, use the system clock app.
How Countdown Timer works
When you start, the timer stores an absolute end time (Date.now() plus the duration, or the chosen target). Every 200 ms, and whenever the tab becomes visible again, the remaining time is recalculated as end time minus now. This means throttled background tabs never make the countdown drift. The alarm is a short beep pattern generated with the Web Audio API (no sound file), and notifications use the browser Notification API after you grant permission. The remaining time also appears in the tab title.
Common Use Cases
- Kitchen or tea timer
- Timeboxing a meeting or exam section
- Counting down to a launch, deadline or New Year
- Short breaks between work sessions
FAQs
Why didn't I hear the alarm?
Browsers only allow sound after you interact with the page. Clicking Start counts as that interaction; also check that the tab and the system are not muted. Use Test sound to check.
Will the timer be wrong if the tab is in the background?
No. Background tabs may update the display less often, but the remaining time is always computed from the fixed end time, so it is correct.
Which time zone is used for the target date?
The time zone of your device, which is shown under the input.
What is the maximum duration?
Up to 100 hours in duration mode. In target mode you can count down to any future date; long countdowns show the number of days plus hours, minutes and seconds.