Set the alarm clock for 4:16 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 4:14 am Alarm clock for 4:15 am Alarm clock for 4:17 am Alarm clock for 4:18 am

Going to bed for a 4:16 am alarm

Asleep by 7:01 pm — 6 full sleep cycles, about 9 hours
Asleep by 8:31 pm — 5 full sleep cycles, about 7 hours
Asleep by 10:01 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.

4:16 am across the country

London	4:16 am
Birmingham	4:16 am
Manchester	4:16 am
Glasgow	4:16 am
Belfast	4:16 am

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

How to use the online alarm clock

While planning your solstice visit to Stonehenge, set the 4:16 am alarm before the morning arrives so the early start is already settled. That leaves a useful margin before 5:00 am for getting dressed, gathering warm layers and checking that everything needed for watching the sunrise is ready by the door.

Your chosen alarm sound should suit both the hour and the people nearby. A gentle tone may be enough if the phone will sit close to you, while a more persistent sound makes sense when you are concerned about sleeping through a quiet alert. Set the volume beforehand and test it briefly at a considerate time. Keep the alarm page open and the phone awake overnight; otherwise the Stonehenge departure could pass without any sound.

Because the journey happens during the night, check the full driving time rather than judging it from daytime traffic. Roads may be quieter at 4:16 am, but temporary closures, unfamiliar rural turns and the walk from parking can still use the spare minutes before sunrise. Add a small travel buffer, note the route before leaving, and place keys, tickets and outdoor clothing together so the alarm leads straight into departure rather than a search around the house.

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.