Run a countdown timer in your browser with an alert at zero and an optional repeat.
Calculations happen locally. We do not send your values to our server.
Entering 5 minutes shows 00:05:00 and counts down to zero before the alert sounds. Hours are not wrapped at 24, so a long timer can start at 25:01:01, and the longest setting is 99:59:59.
Pressing Start records the moment the timer should finish, and the remaining time is recalculated from your device clock several times a second. Because the countdown is based on that end time rather than on counting ticks, a throttled background tab shows the correct value again as soon as you return.
The alert is a sound played by the page, so it needs the tab open and the volume up. A muted device, a sleeping screen or a closed tab will silence it. For cooking, medication or anything where missing the alert matters, keep a phone alarm as a backup.
Enter hours, minutes and seconds, then press Start. The display counts down in hours, minutes and seconds, so 5 minutes shows 00:05:00 and an hour and a half shows 01:30:00. Hours are not wrapped at 24, so a 25-hour timer starts at 25:01:01, and the longest setting is 99:59:59. Pause keeps the remaining time, Reset returns to the entered duration, and Repeat restarts the same countdown automatically when it reaches zero, which suits interval training or regular breaks.
When you press Start the timer records the moment it should finish and recalculates the remaining time from your device clock several times a second. Browsers slow down scripts in background tabs, sometimes to about once per minute, but because the countdown is based on the end time rather than on counting ticks, the display is correct again as soon as you return. The alert sound, however, can only play when the browser lets the page run, so keep the tab visible for time-critical use.
The alert is a short sound played by the page. It will not be heard if the device is muted, the browser tab is muted, the volume is low or the device has gone to sleep, and closing the tab ends the timer. For cooking, medication or anything where missing the alert matters, use a dedicated timer or a phone alarm as a backup. For a daily wake-up time use the Alarm Clock, and for counting down to a date and time use the Countdown tool.
| Input | Result |
|---|---|
0 h 5 min 0 s | 00:05:00 |
0 h 25 min 0 s | 00:25:00 |
1 h 30 min 0 s | 01:30:00 |
25 h 1 min 1 s | 25:01:01 |
99 h 59 min 59 s | 99:59:59 |
Yes. Browsers slow scripts in hidden tabs, sometimes to about once a minute, so the digits may freeze, but the remaining time is recomputed from the end moment and is correct again the instant you switch back. Only the alert sound depends on the tab being allowed to run.
It restarts the same countdown automatically when it reaches zero, which suits interval training, stretching sets or regular breaks. Pause keeps the remaining time, and Reset returns to the duration you entered so you can start the same interval again.
Use this one for a fixed duration from now. For a daily wake-up time use the Alarm Clock, for the time left until a date use the Countdown, and for alternating work and break blocks use the Pomodoro Timer, which switches between them for you.