Online Alarm Clock
Pick a time and a sound, then leave this tab open: it rings at that time, with snooze. A web page can only ring while it is open.
Sound and moreBell
Alarm off
Alarm for 7:00 am
Keep this tab open. A web page can only ring while it is open, the device is awake and the volume is up. For anything important, use your phone’s own alarm too.
Spaceset or stopSsnoozeRturn offFfull screenMmute
How this works: 2 sources, Checked against 1 worked example,
How this works
Sources
How it’s tested
One worked example for this page is checked by automated tests before every release: given the inputs, the tool must show the expected answer.
Privacy
On your device. Nothing you enter or open leaves this browser. About privacy labels
Changes
- Added 10, 20, 30, 45 and 90 second timer pages, each with its own uses, a table and cited facts.
- A timer opened from a link no longer resets on reload, a tap brings the sound back after one, and on phones Start is on the first screen.
- First published.
How a browser alarm works, and its limits
A web page can’t wake a sleeping phone the way its built-in clock app can. This alarm rings only while the tab is open, the device is awake and the volume is up. To make that likely, the page asks the browser to keep the screen on while an alarm is set, but browsers drop that request when you switch tabs, lock the screen or the battery runs low. Plug the device in, leave this page in front and turn the volume up before you rely on it.
That makes it a good fit for a desk or a kitchen: a reminder to leave for a meeting, collect the children, take something out of the oven or end a gaming session at a set time, on a laptop that is open anyway. For waking up, flights, medication or anything else that truly matters, set your phone’s own alarm as well.
- The Screen Wake Lock API lets a page stop the screen dimming or locking, but only for a visible page: the browser releases the lock when the document is hidden or the battery is too low. Source: MDN Web Docs, Screen Wake Lock API.
- Adults should sleep 7 or more hours a night on a regular basis. Source: Watson et al., Recommended Amount of Sleep for a Healthy Adult (AASM and SRS, 2015).
When to set the alarm for 7, 8 or 9 hours of sleep
The time you fall asleep plus 7, 8 or 9 hours. Adults need 7 hours or more a night (AASM and Sleep Research Society).
| Asleep by | 7 h sleep | 8 h sleep | 9 h sleep |
|---|---|---|---|
| 9:00 pm | 4:00 am | 5:00 am | 6:00 am |
| 9:30 pm | 4:30 am | 5:30 am | 6:30 am |
| 10:00 pm | 5:00 am | 6:00 am | 7:00 am |
| 10:30 pm | 5:30 am | 6:30 am | 7:30 am |
| 11:00 pm | 6:00 am | 7:00 am | 8:00 am |
| 11:30 pm | 6:30 am | 7:30 am | 8:30 am |
| 12:00 am | 7:00 am | 8:00 am | 9:00 am |
| 12:30 am | 7:30 am | 8:30 am | 9:30 am |
| 1:00 am | 8:00 am | 9:00 am | 10:00 am |
Frequently Asked Questions
Will the alarm ring if I close the tab or lock my phone?
No, not reliably. A closed tab can’t play anything, and a locked phone usually suspends the browser, so the alarm may stay silent or ring late. Keep the page open on screen with the device plugged in, and use your phone’s built-in alarm for anything you can’t afford to miss.
Can I use this as a wake-up alarm?
Only with care. It works if you leave a laptop, or a plugged-in phone, open on this page overnight with the screen on and the volume up, but a browser can’t guarantee it, so set your phone’s own alarm as a backup. Test the sound at bedside volume first.
Which time zone does the alarm use?
Your device’s. The time you set is read as local time, the same clock shown on your lock screen or in the corner of your computer. If the device changes time zone after you set the alarm, for example after a flight, set it again to be safe.