Online Alarm Clock
An online alarm clock is a free browser-based tool that rings at the time you set β perfect when your phone is off, charging, or on silent mode.
Add New Alarm
Your Alarms (0)
Keep this tab open for alarms to fire. Data stays in your browser β nothing is uploaded.
How to use Online Alarm Clock
- Pick a time β Choose the hour and minute for your alarm.
- Add a label β Name the alarm β e.g. 'Wake up', 'Meeting'.
- Enable and wait β Keep the browser tab open. The alarm rings at the set time.
- Snooze or dismiss β Get 5-minute snooze or dismiss when it rings.
Key features
- Multiple alarms supported
- Custom labels for each alarm
- Sound alert via Web Audio API
- Snooze (5 min) + dismiss
- Alarms saved in browser
- Clear all alarms button
When to Use an Online Alarm Clock
Online alarm clocks are surprisingly useful in situations where your phone isn't ideal β working at your laptop and don't want to unlock your phone, taking a nap where you don't want to set a phone alarm, cooking or baking with a computer nearby, or when your phone is charging in another room. Some people use browser alarms as backup alarms β if their phone fails, the laptop alarm catches them. Others find browser alarms less likely to be mindlessly dismissed because they're on a device they're actively using.
How It Works
The tool uses JavaScript's Date API to track real time and Web Audio API to play an alert tone. When the current time matches your alarm time, the browser plays a two-tone beep pattern (or your custom sound). Because it runs entirely in your browser, there are no servers involved β your alarm times stay on your device.
Best Practices for Browser Alarms
Keep the tab open and visible β some browsers throttle timers in background tabs. Set the alarm 2-3 minutes before you actually need to wake up. Use a loud system volume but mute other browser tabs (music, YouTube). Enable browser notifications for extra reliability. For critical alarms (job interview, flight), also set a backup on your phone.
Limitations to Know
Browser alarms only work while the tab is open and the browser is running. If you close the browser, shut down your laptop, or put it to sleep, the alarm won't fire. They're also dependent on system volume β if your device is muted, you won't hear anything. For critical wake-ups, always use your phone's built-in alarm as primary and this as backup.
Pro tips
- Keep the tab visible β background tabs may get throttled
- Set a backup alarm on your phone for critical wake-ups
- Enable browser notifications for extra reliability
- Label alarms clearly (Wake up, Meeting, Tea timer)
Common use cases
- Backup alarm when phone is off or charging
- Cooking timer for recipes
- Pomodoro-style work sessions
- Meeting reminders while working at laptop
- Napping at desk
Frequently asked questions
Does it work when my browser is closed?+
No β the tab must stay open. For 24/7 alarms, use your phone's built-in alarm.
Will it ring if my laptop is on silent?+
Yes β the sound plays through your browser, independent of system volume (as long as browser isn't muted).
Are my alarms saved?+
Yes β saved in your browser. They'll persist across visits on the same browser.
Can I set multiple alarms?+
Yes β add as many as you need with different labels.
Is it free?+
Yes, 100% free with no signup.
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