Set the alarm clock for 5:04 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 5:02 am Alarm clock for 5:03 am Alarm clock for 5:05 am Alarm clock for 5:06 am

Going to bed for a 5:04 am alarm

Asleep by 7:49 pm — 6 full sleep cycles, about 9 hours
Asleep by 9:19 pm — 5 full sleep cycles, about 7 hours
Asleep by 10:49 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.

5:04 am across the country

London	5:04 am
Birmingham	5:04 am
Manchester	5:04 am
Glasgow	5:04 am
Belfast	5:04 am

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

How to use the online alarm clock

Getting ready now for a 5:04 am start leaves you free to check the tide table, pack a torch and set out your boots before the alarm is needed. This early departure gives you time to reach the rock pools while the shore is quiet, rather than waiting until 6:00 am and losing useful time around low tide.

Your rock-pool trip depends on hearing the signal, so check whether silent mode will suppress browser audio before relying on it. Set the alarm, raise the media volume and test the sound while you are still awake; the usual ringtone setting may not control audio from the browser. Keep the alarm page open and the phone awake overnight, or the rock-pool departure reminder will not sound. A separate alarm on a clock can provide sensible backup if timing is tight.

Preparing for a 5:04 am departure can easily wake everyone else before dawn. Put clothes, keys and outdoor gear near the door earlier in the evening, and avoid searching through cupboards when the house is quiet. Choose an alarm volume that you can hear from close by without carrying into other bedrooms, then silence it promptly. If someone else needs warning, agree on the early start beforehand rather than leaving footsteps, doors and an unexpected alarm to explain it.

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 5:04 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.