Set the alarm clock for 12:40 am

 

Leave this tab open — the alarm only rings while the tab stays open.

The alarm goes off in: ::
 
 

12:40 am across the country

Sydney12:40 am
Brisbane12:40 am
Adelaide12:10 am
Perth10:40 pm
Darwin12:10 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 at 12:40 am in the dead of night usually means a red-eye flight, a delivery run, or a newborn's next feed. This sets a browser alarm for 12:40 am that rings through your laptop speakers, so you don't need to fumble for your phone in the dark. Leave the tab open and it'll do the waking for you.

Start by selecting a tone from the dropdown, then hit Start to lock it in. From that point the page does the counting, and it'll ring once the time is reached, but only if the tab is still open somewhere on your device. Closing it, or the browser entirely, cancels the alarm.

Compared to a phone, this alarm has one job and nothing else competing for attention — no messages, no app switching. It's free and doesn't ask for sign-up, but it only works while the tab is open and the device stays awake, so it suits daytime use at a desk better than an overnight bedroom alarm. On a 24-hour clock 12:40 am is written 00:40, and spoken aloud it's twenty to one at night. Timetables and rosters may show it as 00:40, and handwritten notes as 12.40 am. 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

Is this alarm accurate across daylight saving time?

It uses your device's local clock, so as long as your computer's time and date settings are correct, it'll adjust automatically when daylight saving time starts or ends.

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.