Set the alarm clock for 3:31 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 3:29 am Alarm clock for 3:30 am Alarm clock for 3:32 am Alarm clock for 3:33 am

Going to bed for a 3:31 am alarm

Asleep by 6:16 pm — 6 full sleep cycles, about 9 hours
Asleep by 7:46 pm — 5 full sleep cycles, about 7 hours
Asleep by 9:16 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.

3:31 am across the country

London	3:31 am
Birmingham	3:31 am
Manchester	3:31 am
Glasgow	3:31 am
Belfast	3:31 am

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

How to use the online alarm clock

Watching the clock as an overnight supermarket shift winds down, you can use the 3:31 am alarm as the cue that waiting is over. It leaves 29 minutes before 4:00 am, enough time to finish the remaining aisle checks, tidy the till area and be ready when the scheduled end of the shift arrives.

With colleagues and customers nearby, the alarm’s sound needs checking before you depend on it. Silent mode or a very low media volume may leave only a visual alert, so a brief sound test helps establish what will actually be noticed on the shop floor. The alarm cannot mark the end of the supermarket shift if its browser session has stopped running or the phone or computer has gone to sleep, so it should remain active and awake until 3:31 am.

Near the end of a night shift, a small drink of water or a light snack from the staff room is easier to fit around the final jobs than a full meal. Anything hot, heavy or awkward to pack away can wait until after 4:00 am, when there is no need to abandon it halfway through to sign out, collect belongings or meet the night bus.

Common questions

What happens if my laptop goes to sleep before 3:31 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.