Set the alarm clock for 6:21 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 6:19 am Alarm clock for 6:20 am Alarm clock for 6:22 am Alarm clock for 6:23 am

Going to bed for a 6:21 am alarm

Asleep by 9:06 pm — 6 full sleep cycles, about 9 hours
Asleep by 10:36 pm — 5 full sleep cycles, about 7 hours
Asleep by 12:06 am — 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.

6:21 am across the country

London	6:21 am
Birmingham	6:21 am
Manchester	6:21 am
Glasgow	6:21 am
Belfast	6:21 am

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

How to use the online alarm clock

You are finishing the last checks before leaving to open the public swimming pool for its early session, and a 6:21 am alarm marks the moment to head out. That gives you a clear departure point while leaving enough time to unlock the entrance, switch on the lights and prepare the changing rooms before 7:00 am.

Because the pool opening depends on this reminder, the browser needs to remain active after the alarm is set. If its tab or browser is closed, or the device goes to sleep, the alarm cannot sound and the pool may still be locked when the first swimmers arrive. The chosen tone should also be audible above any radio, shower or cleaning equipment nearby; checking the device’s sound level before finishing your work avoids relying on a muted alert.

As you leave a warm, damp pool building at 6:21 am, the outdoor air may feel unexpectedly cool even when the forecast looks mild. Moist clothing can make that contrast sharper, so a dry outer layer kept near the staff exit is useful for the walk or cycle outside. A moment by the doorway also lets your eyes adjust from bright indoor lighting to the dim early morning before you set off.

Common questions

What happens if my laptop goes to sleep before 6:21 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.