Set the alarm clock for 4:20 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 4:18 am Alarm clock for 4:19 am Alarm clock for 4:21 am Alarm clock for 4:22 am

Going to bed for a 4:20 am alarm

Asleep by 7:05 pm — 6 full sleep cycles, about 9 hours
Asleep by 8:35 pm — 5 full sleep cycles, about 7 hours
Asleep by 10:05 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.

4:20 am across the country

London	4:20 am
Birmingham	4:20 am
Manchester	4:20 am
Glasgow	4:20 am
Belfast	4:20 am

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

How to use the online alarm clock

As you finish up and head out for a coastguard watch, set the alarm for 4:20 am before putting away the last of your things. That leaves a useful stretch before 5:00 am for getting to the station, changing and receiving the handover without turning the departure into a rush.

Your coastguard watch depends on the browser remaining active after the alarm is set. If you close the page or quit the browser, the 4:20 am alarm will not sound; if the phone or computer goes to sleep, it may also stay silent. Leave the alarm page open, keep the device awake and connected to power, and set its volume high enough to be heard while you gather your kit.

Because you will be travelling before dawn, check the route and likely journey time before settling down. Roads may be quiet at 4:20 am, but overnight works, diversions or a longer coastal route can still use much of the time available. Allow a small buffer beyond the normal drive, place keys and identification together, and note where you can park on arrival.

Common questions

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.

What happens if my laptop goes to sleep before 4:20 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.