Online alarm clock
Pick a time, add a label, and it rings then, even if you are working in another tab.
Alarms
No alarms set.
Alarm & notification settings
Sound needs one tap on the page first (a browser rule). Keep this tab open: closing it stops every timer’s alarm. Why timers stay accurate in background tabs.
What an online alarm can and can’t do
This alarm works like the others on CountdownPro: it stores the exact moment it should ring and books the sound on the browser’s audio clock, so a background tab won’t make it late. What no web page can do is ring once it is closed, or reliably wake a phone that has gone to sleep. Keep this tab open with the volume up, and turn on notifications for a pop-up you can see from any app.
For a quick relative alarm (“in 45 minutes”) the countdown timer is faster; for everyone counting down to the same moment, use a shareable countdown link.
Questions
Will this online alarm clock wake me up?
Only if the tab stays open, the device stays awake and the volume is up. A web page cannot ring after it is closed, and phones may silence a locked page. For waking up in the morning, your phone’s built-in alarm app is more reliable; this is best for alarms during the day at a computer.
Can I set more than one alarm?
Yes. Each alarm is added to the list with its own label and rings on its own. They are saved in your browser, so a reload keeps them.
What if the time I pick has already passed today?
The alarm is set for that time tomorrow, and the list shows the date and how long until it rings.