Set the alarm clock for 4:36 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 4:34 am Alarm clock for 4:35 am Alarm clock for 4:37 am Alarm clock for 4:38 am

Going to bed for a 4:36 am alarm

Asleep by 7:21 pm — 6 full sleep cycles, about 9 hours
Asleep by 8:51 pm — 5 full sleep cycles, about 7 hours
Asleep by 10:21 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.

4:36 am across the country

London	4:36 am
Birmingham	4:36 am
Manchester	4:36 am
Glasgow	4:36 am
Belfast	4:36 am

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

How to use the online alarm clock

Finish what you are doing and leave for your shift at a London fire station when the 4:36 am alarm sounds. This gives you a clear departure point without repeatedly checking the time while you gather your keys, pass and outer layer. If you need to be ready before the next round hour, 5:00 am provides a useful final boundary for anything that cannot wait.

Before heading to the station, check where your computer is sending its audio, as headphones may remain selected even after you have taken them off. Play a brief test sound, set a sensible volume, and place the headphones where you will notice any output from them. Do not rely on this browser alarm alone for a fire-station shift: it will not sound once the page is closed or the computer has gone to sleep, so use a separate alarm as backup.

As you leave, pause long enough to listen for the change in the streets around you. At 4:36 am, traffic may still be sparse, but early deliveries, buses and refuse vehicles can begin to break the night-time quiet. Keep reflective clothing visible, avoid assuming an empty road is silent, and allow a moment at crossings to spot vehicles before their engine noise reaches you.

Common questions

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.

Can I use this on a phone?

It works in a mobile browser, but phones lock the screen and suspend background tabs far more readily than a laptop does, which can stop the alarm sounding. For anything important, a desktop or a plugged-in laptop is the steadier option.

Does the alarm still work if I close the tab?

No. Everything runs inside this page, so closing the tab — or quitting the browser altogether — ends the countdown there and then. Leaving it open in the background is all it asks, and switching to another tab makes no difference.