Set the alarm clock for 5:43 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 5:41 am Alarm clock for 5:42 am Alarm clock for 5:44 am Alarm clock for 5:45 am

Going to bed for a 5:43 am alarm

Asleep by 8:28 pm — 6 full sleep cycles, about 9 hours
Asleep by 9:58 pm — 5 full sleep cycles, about 7 hours
Asleep by 11:28 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.

5:43 am across the country

Sydney	5:43 am
Brisbane	5:43 am
Adelaide	5:13 am
Perth	3:43 am
Darwin	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

An alarm for 5:43 am is usually about catching something before the rest of the world is awake: a ferry, a flight, or a change of shift. Set the time, pick a tone, and leave this tab open. At 5:43 am it'll ring through your device's speakers until you tell it to stop.

Select a sound, hit Start, and that's the whole setup. The countdown runs inside this browser tab rather than on your device's operating system, so it needs to remain open, on a phone or laptop, until the alarm actually goes off.

Some people use this alongside a phone alarm rather than instead of it: a louder backup through laptop speakers, or a way to set a reminder without touching a phone at all. It won't survive the tab closing or the device sleeping, so for anything critical overnight, keep a second alarm running as well. On a 24-hour clock 5:43 am is written 05:43, and spoken aloud it's seventeen minutes to six in the morning. You'll also see it written 5.43 am — a full stop instead of the colon means the same time. If you need it loud, turn the system volume up before you start: the alarm plays at whatever the device is set to.

Common questions

Can I use this on my phone instead of a laptop?

Yes, it works in a mobile browser the same way, but phones are more likely to lock the screen or sleep, which can stop the alarm from ringing. A laptop or desktop tends to be more reliable for this.

Can I set more than one alarm at a time?

This page is built around a single alarm at a time. For multiple alarms, open a separate tab for each one and set a different time in each, keeping every tab open until it's rung.

Why use a browser alarm instead of my phone's built-in one?

Mainly for reliability against silent mode, do-not-disturb, or a phone left charging out of earshot. It's a useful backup or a desk-based alternative, though it depends on this tab staying open rather than running in the background of your phone.

Is there a cost to use this?

No, it's free, with no sign-up and no limit on how many times you set it. It just needs the tab left open until the time you've chosen arrives.