Can I set multiple alarms?

The current version supports one active alarm at a time. Open a second browser tab to set additional alarms.

How do I switch between 12-hour and 24-hour time?

Open Settings and choose your preferred format under Time Format. The clock, inputs, and all labels update instantly.

How long is the snooze?

You can configure snooze to 5, 10, 15, or 20 minutes in Settings. The alarm automatically reschedules after you tap Snooze.

Online Alarm Clock — Set a Free Alarm

Q: Does the alarm work in the background?

Yes. The alarm fires even when you switch to another browser tab. Enable browser notifications in Settings for system-level alerts even when minimised.

Q: Is this alarm clock free?

Yes, completely free. No account, no download, no ads.

Q: What happens if I close the tab?

Closing the tab stops the alarm. Keep the ClockUnit tab open (minimised is fine) for the alarm to fire correctly.

Online Alarm Clock

12:00:00AM

No alarm set. Enter a time below.

hour

min

optional label

Quick alarms

Set any alarm in one click

Every preset alarm page opens with the time already filled in and ready to set.

Early Morning

12:00 AM Midnight 12:01 AM Midnight 12:02 AM Midnight 12:03 AM Midnight 12:04 AM Midnight 12:05 AM Midnight 12:06 AM Midnight 12:07 AM Midnight 12:08 AM Midnight 12:09 AM Midnight 12:10 AM Midnight 12:11 AM Midnight 12:12 AM Midnight 12:13 AM Midnight 12:14 AM Midnight 12:15 AM Midnight 12:16 AM Midnight 12:17 AM Midnight 12:18 AM Midnight 12:19 AM Midnight 12:20 AM Midnight 12:21 AM Midnight 12:22 AM Midnight 12:23 AM Midnight 12:24 AM Midnight 12:25 AM Midnight 12:26 AM Midnight 12:27 AM Midnight 12:28 AM Midnight 12:29 AM Midnight 12:30 AM Midnight 12:31 AM Midnight 12:32 AM Midnight 12:33 AM Midnight 12:34 AM Midnight 12:35 AM Midnight 12:36 AM Midnight 12:37 AM Midnight 12:38 AM Midnight 12:39 AM Midnight 12:40 AM Midnight 12:41 AM Midnight 12:42 AM Midnight 12:43 AM Midnight 12:44 AM Midnight 12:45 AM Midnight 12:46 AM Midnight 12:47 AM Midnight 12:48 AM Midnight 12:49 AM Midnight 12:50 AM Midnight 12:51 AM Midnight 12:52 AM Midnight 12:53 AM Midnight 12:54 AM Midnight 12:55 AM Midnight 12:56 AM Midnight 12:57 AM Midnight 12:58 AM Midnight 12:59 AM Midnight 1:00 AM Late night 1:01 AM Late night 1:02 AM Late night 1:03 AM Late night 1:04 AM Late night 1:05 AM Late night 1:06 AM Late night 1:07 AM Late night 1:08 AM Late night 1:09 AM Late night 1:10 AM Late night 1:11 AM Late night 1:12 AM Late night 1:13 AM Late night 1:14 AM Late night 1:15 AM Late night 1:16 AM Late night 1:17 AM Late night 1:18 AM Late night 1:19 AM Late night 1:20 AM Late night 1:21 AM Late night 1:22 AM Late night 1:23 AM Late night 1:24 AM Late night 1:25 AM Late night 1:26 AM Late night 1:27 AM Late night 1:28 AM Late night 1:29 AM Late night 1:30 AM Late night 1:31 AM Late night 1:32 AM Late night 1:33 AM Late night 1:34 AM Late night 1:35 AM Late night 1:36 AM Late night 1:37 AM Late night 1:38 AM Late night 1:39 AM Late night 1:40 AM Late night 1:41 AM Late night 1:42 AM Late night 1:43 AM Late night 1:44 AM Late night 1:45 AM Late night 1:46 AM Late night 1:47 AM Late night 1:48 AM Late night 1:49 AM Late night 1:50 AM Late night 1:51 AM Late night 1:52 AM Late night 1:53 AM Late night 1:54 AM Late night 1:55 AM Late night 1:56 AM Late night 1:57 AM Late night 1:58 AM Late night 1:59 AM Late night 2:00 AM Late night 2:01 AM Late night 2:02 AM Late night 2:03 AM Late night 2:04 AM Late night 2:05 AM Late night 2:06 AM Late night 2:07 AM Late night 2:08 AM Late night 2:09 AM Late night 2:10 AM Late night 2:11 AM Late night 2:12 AM Late night 2:13 AM Late night 2:14 AM Late night 2:15 AM Late night 2:16 AM Late night 2:17 AM Late night 2:18 AM Late night 2:19 AM Late night 2:20 AM Late night 2:21 AM Late night 2:22 AM Late night 2:23 AM Late night 2:24 AM Late night 2:25 AM Late night 2:26 AM Late night 2:27 AM Late night 2:28 AM Late night 2:29 AM Late night 2:30 AM Late night 2:31 AM Late night 2:32 AM Late night 2:33 AM Late night 2:34 AM Late night 2:35 AM Late night 2:36 AM Late night 2:37 AM Late night 2:38 AM Late night 2:39 AM Late night 2:40 AM Late night 2:41 AM Late night 2:42 AM Late night 2:43 AM Late night 2:44 AM Late night 2:45 AM Late night 2:46 AM Late night 2:47 AM Late night 2:48 AM Late night 2:49 AM Late night 2:50 AM Late night 2:51 AM Late night 2:52 AM Late night 2:53 AM Late night 2:54 AM Late night 2:55 AM Late night 2:56 AM Late night 2:57 AM Late night 2:58 AM Late night 2:59 AM Late night 3:00 AM Late night 3:01 AM Late night 3:02 AM Late night 3:03 AM Late night 3:04 AM Late night 3:05 AM Late night 3:06 AM Late night 3:07 AM Late night 3:08 AM Late night 3:09 AM Late night 3:10 AM Late night 3:11 AM Late night 3:12 AM Late night 3:13 AM Late night 3:14 AM Late night 3:15 AM Late night 3:16 AM Late night 3:17 AM Late night 3:18 AM Late night 3:19 AM Late night 3:20 AM Late night 3:21 AM Late night 3:22 AM Late night 3:23 AM Late night 3:24 AM Late night 3:25 AM Late night 3:26 AM Late night 3:27 AM Late night 3:28 AM Late night 3:29 AM Late night 3:30 AM Late night 3:31 AM Late night 3:32 AM Late night 3:33 AM Late night 3:34 AM Late night 3:35 AM Late night 3:36 AM Late night 3:37 AM Late night 3:38 AM Late night 3:39 AM Late night 3:40 AM Late night 3:41 AM Late night 3:42 AM Late night 3:43 AM Late night 3:44 AM Late night 3:45 AM Late night 3:46 AM Late night 3:47 AM Late night 3:48 AM Late night 3:49 AM Late night 3:50 AM Late night 3:51 AM Late night 3:52 AM Late night 3:53 AM Late night 3:54 AM Late night 3:55 AM Late night 3:56 AM Late night 3:57 AM Late night 3:58 AM Late night 3:59 AM Late night 4:00 AM Late night 4:01 AM Late night 4:02 AM Late night 4:03 AM Late night 4:04 AM Late night 4:05 AM Late night 4:06 AM Late night 4:07 AM Late night 4:08 AM Late night 4:09 AM Late night 4:10 AM Late night 4:11 AM Late night 4:12 AM Late night 4:13 AM Late night 4:14 AM Late night 4:15 AM Late night 4:16 AM Late night 4:17 AM Late night 4:18 AM Late night 4:19 AM Late night 4:20 AM Late night 4:21 AM Late night 4:22 AM Late night 4:23 AM Late night 4:24 AM Late night 4:25 AM Late night 4:26 AM Late night 4:27 AM Late night 4:28 AM Late night 4:29 AM Late night 4:30 AM Late night 4:31 AM Late night 4:32 AM Late night 4:33 AM Late night 4:34 AM Late night 4:35 AM Late night 4:36 AM Late night 4:37 AM Late night 4:38 AM Late night 4:39 AM Late night 4:40 AM Late night 4:41 AM Late night 4:42 AM Late night 4:43 AM Late night 4:44 AM Late night 4:45 AM Late night 4:46 AM Late night 4:47 AM Late night 4:48 AM Late night 4:49 AM Late night 4:50 AM Late night 4:51 AM Late night 4:52 AM Late night 4:53 AM Late night 4:54 AM Late night 4:55 AM Late night 4:56 AM Late night 4:57 AM Late night 4:58 AM Late night 4:59 AM Late night

Morning

Afternoon

Evening

Alarm Clock

What is an Online Alarm Clock?

An online alarm clock rings at a specific time you choose instead of counting down from a duration. ClockUnit lets you set a wake-up time, add a label, choose a sound, and keep the alarm ready right in your browser.

How it works

How to Set an Alarm

Three steps, fifteen seconds.

Choose the alarm time

Enter the hour and minute, then pick AM or PM if you are using 12-hour time.

Set the alarm

Press Set Alarm and ClockUnit starts watching the clock for that exact time.

Dismiss or snooze

When the alarm fires, dismiss it to stop or snooze it using your chosen snooze interval.

Features

Everything You Need in an Alarm Clock

Built for reliability, clarity, and exact time-based reminders.

🔔

Reliable Alarm

Set a specific clock time and let ClockUnit ring until you dismiss or snooze the alert.

😴

Snooze Built In

Snooze the alarm for 5, 10, 15, or 20 minutes without resetting the original setup.

🕐

12h and 24h Time Formats

Switch between AM/PM and 24-hour time in Settings and the entire alarm interface updates instantly.

🌐

Works in Your Browser

No download, no account, and no extra app required. Open the page, set the time, and leave the tab running.

🔕

Clear Active Alarm State

See your next alarm time, how long remains until it rings, and any custom label you added.

🖥️

Optional Browser Notifications

Enable notifications if you want an extra system-level prompt when the alarm fires in the background.

Use cases

When to Use an Online Alarm Clock

Exact time reminders for mornings, afternoons, evenings, and everything between.

⏰

Morning wake-up

Set a simple wake-up alarm without opening your phone clock app.

💊

Medication reminders

Create exact-time alarms for medication schedules or midday reminders.

🍳

Cooking reminders

Use an alarm for exact check times when you care about the clock more than the duration.

📋

Meetings and calls

Set a warning alarm before an important meeting so you can wrap up and join on time.

😴

Power naps

Set a wake-up alarm before a nap so you rest without oversleeping into the day.

🏋️

Workout transitions

Use alarms for class starts, training blocks, or exact rest-end reminders.

FAQ

Online Alarm Clock — FAQ

Does the alarm work in the background?

Yes. If the ClockUnit tab stays open, the alarm can fire while you work in another tab or window. Browser notifications can add an extra system-level alert.

Can I use a custom label for the alarm?

Yes. You can add a short label like Wake up, Meeting, or Medication so the ringing alert is easier to identify.

Can I switch between 12-hour and 24-hour time?

Yes. Open Settings and change the time format. The display, inputs, and preset labels all update immediately.

What happens if I close the tab?

Closing the tab stops the alarm. Keep the ClockUnit alarm tab open in the background for it to ring correctly.

Can I snooze the alarm?

Yes. When the alarm rings, you can snooze it using the snooze duration chosen in Settings.

Is this alarm clock free?

Yes. ClockUnit's online alarm clock is free to use with no account or download required.