Set the alarm clock for 5:03 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 5:01 am Alarm clock for 5:02 am Alarm clock for 5:04 am Alarm clock for 5:05 am

Going to bed for a 5:03 am alarm

Asleep by 7:48 pm — 6 full sleep cycles, about 9 hours
Asleep by 9:18 pm — 5 full sleep cycles, about 7 hours
Asleep by 10:48 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.

5:03 am across the country

London	5:03 am
Birmingham	5:03 am
Manchester	5:03 am
Glasgow	5:03 am
Belfast	5:03 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 just waking at 5:03 am, with your Thames rowing session still ahead rather than under way. Setting an alarm now gives you a clear point to get out of bed, dress for the river and gather your kit without drifting back to sleep. With 6:00 am approaching, there is still time for a calm start before you leave.

Your rowing morning may already include the hum of heating, running water or someone moving around the house, so set the volume high enough to stand apart from that background noise. Keep the phone close, but not buried under bedding or inside a kit bag where the sound will be muffled. This alarm stops being dependable once the browser is dismissed or the phone goes to sleep, so your Thames rowing session needs a separate alarm if you cannot keep it active.

Before heading towards the river in the early morning, work backwards from whatever follows training later that day. Allow time for changing, travelling home and dealing with wet gear, then leave a small buffer before work, study or another commitment. That spare margin makes a 5:03 am start useful without letting the rowing session squeeze everything that comes afterwards.

Common questions

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.

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.