Free Online Alarm Clock

Online Alarm Clock
Never Miss a Moment

Set custom alarms with sounds, repeat schedules, and browser notifications. No signup required.

Set New Alarm

:

7:00 AM

Your Alarms (0)

No alarms set

Add your first alarm above

Features

Custom Sounds

Choose from multiple alarm tones

Repeat Schedules

Set daily or weekday alarms

Browser Notifications

Get alerts even when tab is inactive

Persistent Storage

Alarms saved in your browser

How to Set an Alarm in 3 Steps

01

Choose Your Time

Use the hour and minute inputs to set your desired alarm time. The clock displays time in 12-hour format with AM/PM indicators for easy reading.

02

Customize Your Alarm

Add a descriptive label to identify your alarm, select a repeat pattern (once, daily, or weekdays), and choose from multiple alarm sounds to match your preference.

03

Enable Notifications

Allow browser notifications when prompted. This ensures you receive alerts even when the Castimer tab is not active. Your alarms are automatically saved in your browser.

Why Use an Online Alarm Clock?

No Installation Required

Access your alarm clock from any device with a web browser. No app downloads or updates needed. Works on desktop, tablet, and mobile devices.

Perfect for Remote Work

Set alarms for meetings, breaks, and end-of-day reminders. Keep your work schedule organized without relying on your phone or physical clock.

Multiple Alarm Management

Create and manage multiple alarms for different purposes. Label each alarm to stay organized—work meetings, personal reminders, or daily routines.

Privacy-Focused Design

All alarm data is stored locally in your browser. No account creation required, no data sent to servers. Your schedule stays private and secure.

Frequently Asked Questions

Will my alarm work if I close the browser tab?

The alarm will trigger as long as the tab remains open. For best results, keep the Castimer tab open in your browser. Browser notifications will alert you even if you are working in another tab.

How many alarms can I set?

You can set unlimited alarms. All alarms are stored in your browser's local storage, so there is no server-side limit. However, clearing your browser data will remove saved alarms.

Can I use this alarm clock on my phone?

Yes, the online alarm clock works on any device with a modern web browser, including smartphones and tablets. For reliable alerts, keep your device awake and the tab active.

Do I need to create an account?

No account or signup is required. Simply visit the page, set your alarm, and allow browser notifications. Your alarms are saved automatically in your browser.

What happens if I refresh the page?

Your alarms are automatically saved in your browser's local storage. When you refresh or revisit the page, all your saved alarms will be restored.