Set the alarm clock for 8:21 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 8:19 am Alarm clock for 8:20 am Alarm clock for 8:22 am Alarm clock for 8:23 am

Going to bed for a 8:21 am alarm

Asleep by 11:06 pm — 6 full sleep cycles, about 9 hours
Asleep by 12:36 am — 5 full sleep cycles, about 7 hours
Asleep by 2:06 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.

8:21 am across the country

Sydney	8:21 am
Brisbane	8:21 am
Adelaide	7:51 am
Perth	6:21 am
Darwin	7:51 am

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

How to use the online alarm clock

Uni lectures, gym sessions before work, or just a second alarm because the first one never works: 8:21 am is a popular time to want a backup. This rings from your browser at 8:21 am. No app store, no sign-up, just a tab that needs to stay open until it fires.

Pick whichever sound you're most likely to actually notice, then press Start. The alarm is tied to this browser tab, so it needs to stay open. Minimising the window is fine, but closing the tab or the browser will stop the countdown before it ever rings.

A browser alarm like this one is handy when your phone's on silent, charging in another room, or you just don't want to unlock it and get pulled into notifications. The trade-off is honesty: it only rings while this tab stays open, so it's not a replacement for your phone alarm on a trip where the laptop lid might close. On a 24-hour clock 8:21 am is written 08:21, and spoken aloud it's twenty-one minutes past eight in the morning. Timetables and rosters may show it as 08:21, and handwritten notes as 8.21 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

What happens once the alarm goes off?

It rings through your device's speakers on a loop until you stop it from this page. There's no separate app notification, so make sure your volume is turned up before you rely on it.

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.