Online Alarm Clock - Free Web Alarm | Set Alarm for Any Time

Free Online Alarm Clock — Set an Alarm on Your Computer

OnlineAlarm.org is a free online alarm clock that runs entirely inside your web browser. There is nothing to download or install — just pick a time, choose a sound, and click Set Alarm. The alarm works on Windows, Mac, Chromebook, iPhone, iPad, and Android — any device with a modern browser and speakers.

Whether you need a wake-up alarm, a reminder for a meeting, an alert for a study break, or a nudge to take medication, our alarm clock has you covered — completely free, with no sign-up required.

How to Set an Alarm Online

Setting an alarm with our online alarm clock takes only a few seconds:

Choose the hour and minute — Use the dropdowns or tap a quick-set button (5:00 AM, 6:00 AM, 7:00 AM, etc.) to set the alarm instantly.
Pick an alarm sound — Choose from 12 alarm tones: Classic, Clock, Siren, Flute, Alien, Birds, Buzzer, Childhood, Mystic, Nuclear, Rain, or Rooster. Press the play button to preview before setting.
Name your alarm (optional) — Add a label like “Wake Up” or “Take Pills” so you remember why it went off.
Click “Set Alarm” — A live countdown timer appears showing the hours, minutes, and seconds until the alarm rings. The browser tab title also updates with the countdown so you can track it from another tab.

When the countdown hits zero, your chosen alarm sound plays at full volume. You can Stop the alarm or press Snooze to delay it by 10 minutes.

💡 Tip: Open multiple browser tabs to set multiple alarms at the same time — each tab runs independently.

Features of Our Online Alarm Clock

12 alarm sounds — From gentle Birds and Rain to urgent Siren and Nuclear. Preview any sound before setting your alarm.
Quick-set presets — One-tap buttons for popular wake-up times: 5:00 AM, 5:30 AM, 6:00 AM, 6:30 AM, 7:00 AM, 7:30 AM, 8:00 AM, and 8:30 AM.
Snooze button — Adds 10 extra minutes of sleep when the alarm goes off.
Custom alarm name — Label each alarm with a message that displays during the countdown.
Live countdown in tab title — See the remaining time even when you're in another tab.
Progress bar — A visual indicator that shrinks as the countdown approaches zero.
Auto-save settings — Your last-used hour, minute, sound, and alarm name are remembered for next time.
Fully responsive — Large clock display works beautifully on phones, tablets, and desktops.
Dark & light mode — Automatically matches your system theme or toggle manually.

Set Alarm for a Specific Time

Use these direct links to quickly set an alarm for a specific time:

When to Use an Online Alarm Clock

Waking up — Set a morning alarm on your laptop or desktop when your phone is charging in another room.
Power naps — Set a 20- or 30-minute alarm for a quick afternoon nap. Try our Online Timer for exact minute countdowns.
Study sessions — Combine with the Pomodoro Timer for focused 25-minute work blocks.
Cooking & baking — Set an alarm so you never forget what's in the oven.
Meetings & calls — Get reminded 5 minutes before your next Zoom call.
Medication reminders — Set daily alarms to take pills on time.
Exam practice — Simulate timed test conditions with a custom alarm name like “Time's Up!”

Will the Alarm Work If the Tab Is Closed?

No — the alarm requires the browser tab to remain open. However, you can switch to another tab or use other apps while the alarm tab stays open in the background. The alarm will still ring and the sound will play as long as the browser is running.

Does the Alarm Work in Sleep Mode?

Display off only: If your computer screen turns off but the system stays awake, the alarm will still ring in most cases.
Sleep / Hibernate: The alarm will not ring if the computer enters sleep or hibernate mode. Adjust your power settings to prevent sleep, or use your phone's built-in alarm as a backup.
Shutdown: The alarm will not work when the computer is turned off.

💡 Pro tip: On Windows, go to Settings → System → Power & Sleep and set sleep to “Never” while using the alarm. On Mac, use System Settings → Energy Saver to prevent sleep.

Is the Online Alarm Clock Loud Enough?

The alarm volume depends on your device speakers and system volume level. For the best experience:

Turn your system volume to at least 80%.
Make sure your device is not on silent or mute.
Disable Do Not Disturb or Focus mode.
Use external speakers or headphones for louder alerts.
Preview the alarm sound beforehand to test the volume.

Explore More Free Tools

OnlineAlarm.org offers a complete suite of free time tools:

Online Timer — Set a countdown timer with hours, minutes, and seconds.
Online Stopwatch — Track elapsed time with lap recording.
World Clock — View current time in 45+ cities around the globe.
Pomodoro Timer — Boost productivity with 25/5 or custom work/break intervals.
Date Countdown — Count down to holidays, birthdays, and special events.
Time Zone Converter — Convert time between any two cities instantly.
Age Calculator — Find your exact age in years, months, days, and more.
Date Calculator — Calculate the difference between two dates or add/subtract days.

Frequently Asked Questions

How do I set an alarm on my computer?

Visit OnlineAlarm.org, select the hour and minute, pick an alarm sound, and click Set Alarm. Keep the tab open and the alarm will ring at the scheduled time. No download or account required.

Can I set multiple alarms at once?

Yes. Open a separate browser tab for each alarm and configure them independently. Each tab runs its own countdown and plays its own chosen sound.

Does the alarm work on my phone?

Yes. OnlineAlarm.org works on iPhone, Android, and iPad browsers (Safari, Chrome, Firefox). Make sure your phone is not on silent mode and the browser tab stays open.

Why can't I hear the alarm?

Common reasons include: device volume set to zero, silent or mute mode enabled, Do Not Disturb turned on, or the browser tab was closed. Ensure volume is up, DND is off, and the tab remains open.

Is this alarm clock really free?

Yes — 100% free with no sign-up, no ads that block the alarm, and no limitations. Use it as many times as you want on any device.

Can I use it as a bedside clock?

Absolutely. The large clock display with the current time and date makes it perfect as a fullscreen bedside clock. Enable dark mode for a comfortable nighttime display.