Time & date
Online Alarm Clock
Set one or more alarms in your browser, with labels, repeat days, snooze and a big clock. Keep the page open and the device awake.
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No alarms set
Set an alarm
Make sure it rings
- Keep this page open and the device awake. A web page can’t wake a sleeping computer or phone, and closing the tab cancels the alarms. Plug in the charger and turn the volume up.
- Press Test sound once before you rely on an alarm, so you know it is loud enough.
Alarms are saved in this browser only and sounds are made on your device. Nothing is uploaded.
Works in your browser. No account needed.
Frequently asked questions
Will the alarm ring if I close the tab or my computer goes to sleep?
No. A web page can only make sound while it is open, and it can’t wake a sleeping device. Closing the tab cancels the alarms until you come back, and if the laptop lid is shut or the phone locks and sleeps, nothing runs. Keep the page open, plug the device in and set its sleep setting to never while you rely on it. If the device was asleep at alarm time, the page lists the missed alarm when it wakes, and one up to 30 minutes late still rings.
Does it work in a background tab?
Usually, but a tab in front is more reliable. Browsers slow down timers in background tabs to save power; Chrome, for example, can limit a hidden page to about one check a minute. This page uses a separate background timer to keep checking once a second, and the alarm sound itself is scheduled ahead of time, but some browsers pause background tabs entirely, especially on phones. If an alarm rings late, the page says by how much.
Why do I have to click the page before the alarm can make a sound?
Browsers block web pages from playing sound until you interact with them, so a page can’t start making noise on its own. Setting an alarm, pressing Test sound or clicking anywhere unlocks sound for the rest of the visit. If you reload the page, click once again; a reminder appears when saved alarms are waiting and sound is still blocked.
What does Keep the screen on do?
It uses the Screen Wake Lock feature of modern browsers to stop the display dimming and the device going to sleep while alarms are set. It only works while this tab is visible, and it is dropped when you switch tabs or minimise the window, then taken again when you come back. Some browsers don’t support it; there, change the device’s own sleep settings instead.
Are the alarm sounds loud enough to wake me?
They are played through your device’s speakers at the volume on this page times your system volume, so turn the system volume up and use Test sound first. Classic beeps and Digital alarm are sharp and insistent, Chimes is softer, and Gentle rise starts quietly and grows to full volume over about 45 seconds. The sounds are generated by the page itself with the Web Audio API, so there is nothing to download.
Are my alarms saved?
Yes, in this browser’s local storage on this device, together with your volume and 12- or 24-hour choice, so they are still there when you reopen the page. They aren’t sent anywhere and don’t sync to other devices. A one-time alarm switches itself off after it rings; repeating alarms stay on for their chosen days.
About this tool
This online alarm clock turns any computer, tablet or phone with a browser into a bedside or desk alarm. Set up to 20 alarms, each with its own label, sound and snooze length, and have them repeat on weekdays, weekends or any days you choose. The large clock shows the time to the second, in 12- or 24-hour format, with the next alarm and a countdown to it underneath.
It is honest about what a web page can and can’t do. An alarm here rings only while the page is open and the device is awake: a browser tab can’t wake a sleeping laptop, and closing the tab cancels it. To help, the page keeps the screen on with the Screen Wake Lock where the browser supports it, checks the time from a background timer that browsers slow down less, can show a notification as a second alert, and tells you if an alarm was missed or rang late because the tab was paused.
The four sounds are made on your device with the Web Audio API rather than downloaded files: classic bedside beeps, a two-tone digital alarm, bell-like chimes and a gentle tone that starts quietly and rises to full volume. Press Test sound to hear the one you picked at the volume you set. Snooze repeats the alarm after 5, 9, 10, 15 or 20 minutes, as many times as you like.
Times follow your device’s clock and time zone. Repeating alarms keep their wall-clock time across daylight-saving changes, so a 7:00 alarm still rings at 7:00 the morning after the clocks change; an alarm set inside the hour that is skipped when clocks go forward, such as 2:30, rings an hour later by the clock, at 3:30. Alarms and settings are stored only in this browser and never uploaded.