Set the alarm clock for 8:18 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 8:16 am Alarm clock for 8:17 am Alarm clock for 8:19 am Alarm clock for 8:20 am

Going to bed for a 8:18 am alarm

Asleep by 11:03 pm — 6 full sleep cycles, about 9 hours
Asleep by 12:33 am — 5 full sleep cycles, about 7 hours
Asleep by 2:03 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.

8:18 am across the country

London	8:18 am
Birmingham	8:18 am
Manchester	8:18 am
Glasgow	8:18 am
Belfast	8:18 am

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

Online alarm clock for 8:18 am

While you prepare in advance for a tide-pool hunt, set the alarm for 8:18 am before packing your waterproofs, towel and tide-table notes. That gives you a clear cue to finish getting ready and leave for the shore, rather than watching the clock while sorting your kit. You can still be on your way comfortably before 9:00 am.

Because your departure depends on hearing the alert, keep this alarm page open after setting it and leave your phone or computer awake with the sound turned up. If you close the page or browser, or let the device go to sleep, the tide-pool hunt may begin without an alarm sounding. Check the volume with enough time to correct it, and avoid relying on headphones that you might remove while pulling on boots or loading the car.

For an early coastal start, protect some space between the 8:18 am alarm and whatever comes next that day. Allow for finding parking, walking down to the beach and rinsing sandy gear afterwards, especially if the access path is longer than expected. A little spare time also means you can follow the safe tidal window without rushing away merely because a later appointment is approaching.

Common questions

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.

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 8:18 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.