Set the alarm clock for 10:21 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 10:19 am Alarm clock for 10:20 am Alarm clock for 10:22 am Alarm clock for 10:23 am

Going to bed for a 10:21 am alarm

Asleep by 1:06 am — 6 full sleep cycles, about 9 hours
Asleep by 2:36 am — 5 full sleep cycles, about 7 hours
Asleep by 4:06 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.

10:21 am across the country

Sydney	10:21 am
Brisbane	10:21 am
Adelaide	9:51 am
Perth	8:21 am
Darwin	9:51 am

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

How to use the online alarm clock

Between the commute and the first coffee, 10:21 am is often the last checkpoint before the day properly starts. This tool sets a browser alarm for 10:21 am that rings through your device's speakers, handy for a desk you're already sitting at or a laptop open on the kitchen bench.

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.

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 10:21 am is written 10:21, and spoken aloud it's twenty-one minutes past ten in the morning. You'll also see it written 10.21 am — a full stop instead of the colon means the same time. Whether you would say set alarm for 10:21 am or put an alarm on for 10:21 am, the steps are the same: pick a sound, press Start, leave the tab open.

Common questions

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.

Does the alarm work if my laptop goes to sleep?

Not reliably. If the device sleeps or the screen locks, the browser tab pauses along with it, so the alarm may not fire on time or at all. Adjust your power settings if you're relying on this over a longer stretch.

Do I need to create an account or download anything?

No, there's nothing to sign up for and nothing to install. Pick a time and a sound, press Start, and it runs entirely in this browser tab.