Set the alarm clock for 5:13 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 5:11 am Alarm clock for 5:12 am Alarm clock for 5:14 am Alarm clock for 5:15 am

Going to bed for a 5:13 am alarm

Asleep by 7:58 pm — 6 full sleep cycles, about 9 hours
Asleep by 9:28 pm — 5 full sleep cycles, about 7 hours
Asleep by 10:58 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.

5:13 am across the country

London	5:13 am
Birmingham	5:13 am
Manchester	5:13 am
Glasgow	5:13 am
Belfast	5:13 am

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

How to use the online alarm clock

You have only just woken at 5:13 am, with nothing started yet and a building-site arrival to make before rush hour. Set the alarm for the point when you must stop getting ready and leave, allowing for quiet residential streets that can quickly feed into busy commuter routes. Reaching the site before 6:00 am may also leave time to find the correct entrance and put on your work gear.

Your building-site journey should not be the first occasion on which you hear the signal. Set a short test alarm now, keep the volume at the level you intend to use, and check that the sound is distinct enough to notice while you are gathering your things. This browser alarm cannot protect the building-site departure if its page is closed or the phone is allowed to sleep, because the signal may never play; keep both active until it sounds.

Preparing for an early building-site start often means looking at a bright screen in a dim bedroom. Lower the display brightness before checking 5:13 am again, use the warmer colour setting if your phone has one, and place it where the alarm remains audible without shining directly towards your face. Once the time is set, leave the screen alone while dressing, making tea, and collecting keys or PPE.

Common questions

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.

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.