Online Alarm Clock

The page shows a large live clock in your local time, using the time format of your device. The alarm needs a few settings and one click.

1. Choose Alarm time with the time picker. It starts at 07:00, and your browser may show it with AM and PM.
2. Type a Label (optional) such as Meeting or Tea. The label appears while the alarm is set and in the tab title when it rings.
3. Pick a Sound: Classic beeps, Soft chime or Urgent siren.
4. Leave Keep ringing until I stop it ticked if you want repeated sounds, or untick it for a single short ring.
5. Press Set alarm. A line under the clock reads, for example, Alarm set for 07:00, in 8 h 15 min. The button now says Cancel alarm.
6. When it rings, press Stop alarm or Snooze 5 min. The Full screen button turns the clock into a large display for a desk.

Pressing Set alarm also satisfies the browser rule that sound may only start after you click or tap something, so the click is not a formality. If you change the time while an alarm is set, the alarm is set again for the new time.

The tool picks the next moment your clock shows the chosen time. If that time is still ahead today, the alarm is for today. If it has already passed, the alarm is for tomorrow. Suppose it is 10:45 PM and you set 07:00. The next 07:00 is the following morning, 8 hours and 15 minutes away, which is the figure the status line shows and updates. The alarm fires at the start of the chosen minute, so setting 07:00 at 07:00:30 schedules tomorrow, not an instant ring.

When the time arrives, the tab title flashes with the alarm icon and your label, and the sound plays. The three sounds are generated in the browser with the Web Audio API, so there is nothing to download and no connection is needed once the page has loaded.

Where the browser supports it, the screen is kept awake while an alarm is set, so the display does not dim and put the page to sleep. That can use extra battery, which is one more reason to plug in a laptop or phone used as a bedside clock.

This is an alarm that lives inside a web page, and that comes with real limits. Please read them before you rely on it.

• The tab must stay open and the device must stay awake. A phone that locks its screen, a laptop that goes to sleep or a browser that closes the tab to save memory will not ring.
• The device must not be muted. Battery saver modes that freeze background tabs can also stop the clock from checking the time.
• The alarm is not saved. Reloading the page or closing the tab clears it.
• There is one alarm at a time and it fires once per set. There are no repeat days and no list of alarms.
• Browsers allow sound only after a click, which is why you set the alarm with a button press.

For these reasons, treat the page as a convenience, not as a safety device. Use the alarm built into your phone for early flights, medicine times, school runs or anything where missing the sound has a cost. A good habit is to run a test first: set the alarm one minute ahead, press Set alarm, wait for the sound and check the volume.

The online alarm clock suits short, low-stakes jobs on a screen you are already using: a nap at a desk, a cooking reminder, the start of a meeting, a study break or a second alarm next to your phone. The big display with Full screen also works as a plain desk clock.

An alarm and a timer answer different questions. An alarm waits for a time on the clock, such as 3:30 PM. A timer counts down a length of time, such as 25 minutes. For a duration, use the countdown timer, the egg timer for kitchen counts, or the Pomodoro timer for study and work blocks. To measure elapsed time upward, use the online stopwatch.

If you are not sure how long it is until your target time, the time calculator adds and subtracts durations and finds the span between two clock times. The alarm uses the clock of your own device, so for a call in another city check the hour with the time zone converter first and then set the alarm in your own local time.