Set the alarm clock for 4:49 am

Leave this tab open — the alarm only rings while the tab stays open.

The alarm goes off in: ::

You can also try the other alarm clocks

Alarm clock for 4:47 am Alarm clock for 4:48 am Alarm clock for 4:50 am Alarm clock for 4:51 am

Going to bed for a 4:49 am alarm

Asleep by 7:34 pm — 6 full sleep cycles, about 9 hours
Asleep by 9:04 pm — 5 full sleep cycles, about 7 hours
Asleep by 10:34 pm — 4 full sleep cycles, about 6 hours

A sleep cycle runs about 90 minutes, and most people take around 15 minutes to drop off. Waking at the end of a cycle feels easier than waking in the middle of one.

4:49 am across the country

London	4:49 am
Birmingham	4:49 am
Manchester	4:49 am
Glasgow	4:49 am
Belfast	4:49 am

Times are worked out live in your browser, so daylight saving is already accounted for.

How to use the online alarm clock

While you are finishing the current log entry, a 4:49 am alarm can pull you away in time to take over the shift at an Underground control room. That leaves a short, deliberate gap before 5:00 am for handing over notes, checking the panel and being ready when responsibility changes. Treat the sound as the point to stop the task in front of you, not merely as background noise.

Because the prompt has to cut through work already under way, test its sound and volume before relying on it. Set the alarm, use the preview if available, and check that it is clearly audible above the control-room surroundings. This browser alarm can only sound while it remains active, so the Underground shift could lose its prompt if the computer is put to sleep or the page is closed. For a critical handover, keep an authorised workplace alert as a separate safeguard.

Once the overnight duties are handed across, leave a little space before the next job on the same day. At this hour, jot down any follow-up that cannot be completed immediately and assign it a specific later time. That keeps the 4:49 am signal tied to the handover while preserving enough breathing room for the next scheduled responsibility.

Common questions

What happens if my laptop goes to sleep before 4:49 am?

The tab sleeps along with it and the alarm will not sound on time, if at all. If you are relying on it, change the power settings so the machine stays awake, or keep a phone alarm running as well.

Do I need an account or an app?

Neither. Choose a time and a sound, press Start, and it runs in this browser tab. Nothing is downloaded, nothing is registered, and closing the page leaves nothing behind on the device.

Can I change the sound?

Yes, there is a short list of tones to pick from before you press Start. Softer sounds are easy to sleep through, so a firmer bell tends to be the safer choice for anything early in the morning.

Will it still be right when the clocks change?

Yes. It reads your device's local clock, so the move between GMT and BST at the end of March and October is picked up automatically, as long as the computer's date, time and time zone are set correctly.