Online Alarm Clock
Set a web-based alarm clock with custom time. Works in your browser without any app.
About this calculator
Set an alarm for any time and your browser will ring when it arrives. No app, no sign-up.
Keep the tab open: browsers pause timers in sleeping or closed tabs.
How to use it
- Pick the alarm time.
- Press Set Alarm.
- Keep the tab open and the sound on.
How browser alarms work
The page checks the clock every second and rings when the time matches. Because it depends on the page running, closing the tab, putting the computer to sleep or muting the browser will stop it. Do not use it for critical wake-ups. Use your phone's alarm for that.
Worked example
Examples
| Study break | Set the time 25 minutes from now |
| Meeting reminder | Set 5 minutes before the call |
Tips and common mistakes
- Test the sound once.
- Keep your device awake and plugged in.
- Allow audio for the site.
- Use your phone's alarm for anything important.
- Keep the tab visible.
Frequently asked questions
Will it ring if I close the tab?
No.
Does it work offline?
Yes once loaded.
Can I set several?
One at a time.
Why didn't it ring?
The tab may have been suspended or muted.
Is it accurate?
To within a second.
Is it free?
Yes.