How to use the online alarm clock
Setting an alarm for 12:39 am while everyone else is asleep can feel like cheating the clock, but it's usually just planning ahead for an early departure or a shift that starts before sunrise. This will sound at 12:39 am through your speakers, whether it's the depths of winter or a short summer night.
Using it is simple: pick a ringtone from the list, press Start, and leave this tab open in your browser. The alarm runs entirely on this page, so closing the browser will stop it from going off. Come back a minute early if you're not sure you trust it yet.
This works well as a second alarm, one that isn't tangled up with phone notifications, do-not-disturb settings, or low battery. It genuinely won't ring if the tab gets closed or the device goes to sleep, so treat it as a backup or a work-desk tool rather than the only alarm for something important. On a 24-hour clock 12:39 am is written 00:39, and spoken aloud it's twenty-one minutes to one at night. You'll also see it written 12.39 am — a full stop instead of the colon means the same time. Whether you would say set alarm for 12:39 am or put an alarm on for 12:39 am, the steps are the same: pick a sound, press Start, leave the tab open.
Common questions
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.
Will the alarm still ring if I close the browser tab?
No. The alarm only runs while this tab stays open — closing it, or closing the browser entirely, stops the countdown before it can ring. Keep the tab open in the background if you need it to go off later.
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