Online Timer
Set a countdown timer in seconds — presets, custom durations and a choice of alarms.
Quick presets
Custom duration
Alarm sound
How to use the timer
- 1
Pick a quick preset (1, 5, 10, 15, 30 or 60 minutes) or type a custom HH:MM:SS duration.
- 2
Press Start — the timer counts down with a big, clear display and a progress ring.
- 3
Choose an alarm sound from the picker; it plays when the timer reaches zero.
- 4
Optionally enable browser notifications so you are alerted even after switching tabs.
- 5
Use Pause, Reset or the +1:00 button to adjust on the fly, and Share the link to send a pre-set timer.
Tips & tricks
The timer is accurate to the system clock. It calculates the finish time from a real timestamp, so it will not fall behind even if the tab is in the background or your phone sleeps — the alarm still fires on time.
Every timer is shareable. The duration is saved in the page URL, so a link like ?d=300 opens a ready-to-go 5-minute timer. Add &autostart=true and it begins counting the moment the page loads — handy for teachers and trainers.
Pick an alarm that suits the room: a gentle Bell or Chime for an office, the Digital alarm or Air horn when you need to be heard. On phones the timer also vibrates, and it can show a system notification if you grant permission.
Frequently asked questions
How do I set a timer online?
Choose a preset or type a custom duration in HH:MM:SS, then press Start. The timer counts down and plays your chosen alarm when it reaches zero.
Will the alarm go off if I switch tabs or turn off my phone screen?
Yes. The timer tracks real elapsed time and uses a background-safe fallback, so the alarm sound and notification still fire when the timer ends, even if the tab is not in focus.
Can I share a timer with someone?
Yes. The duration is stored in the URL. Use the Share button to copy the link — for example /timer?d=600 is a 10-minute timer. Add &autostart=true to make it start automatically.
Why isn't the alarm sound playing?
Mobile browsers require one tap on the page before they allow audio — press any button once and sound will work. Also check that your phone is not on silent, as the hardware mute switch can block web audio.
Can I add time while the timer is running?
Yes. Use the +1:00 button to extend a running timer without resetting it. You can also pause and resume at any point.
Does the online timer work without internet?
Once the page has loaded it runs entirely in your browser, so a brief connection drop will not stop the countdown.
Is there a limit on the timer length?
No. You can set anything from a few seconds up to many hours.
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