Free alarm
Wake me up in 90 minutes
The alarm below is already set to 90 minutes from now — press Set alarm and leave this tab open. Below, what a 1h 30m sleep actually does, and how to come out of it well.
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90 minutes and up: sleep in whole cycles
From about 90 minutes, you are not napping any more — you are sleeping. A full sleep cycle runs roughly 90 minutes through light sleep, deep sleep and REM, and waking at the end of one feels dramatically better than being pulled out of the middle. That is why 90 minutes is the classic long-nap length, and why 3 hours (two cycles) beats 2 hours for many people even though it is more sleep — 2 hours tends to land the alarm mid-cycle.
The other thing that changes at this length is the wake-up itself. After a cycle or two your body treats the alarm as a morning: expect real disorientation for a minute, especially if you slept in the afternoon and wake to a dark room. Give yourself a landing strip — light, water, a reason to stay vertical — the same way you would at 6 a.m.
If you are doing this at night — a shift worker sleeping before work, a student before an early start — you are really choosing a bedtime, and the sleep calculator or the per-bedtime pages will do the whole night's arithmetic for you, not just this block.
Waking up from it
Whatever the length, the last step is the same: the alarm has to end with you upright. A browser alarm's Stop button is one click away, and one click is well within reach of a brain that is still mostly asleep — which is fine for a desk nap and risky for anything you genuinely must wake up from.
If the stakes are real — a shift, a flight, an exam — put the alarm on your iPhone across the room instead. WakeUpBroo has no snooze and no dismiss button; it stops only when you type a rotating code from wakeupbroo.com/code on the screen you left over here. The walk is what actually ends the sleep.
Other durations
Shorter on time? Try wake me up in 1 hour. Got longer? See wake me up in 2 hours. For a wake-up at a specific clock time, use the online alarm clock or jump straight to a time like 6:00 AM.
FAQ
Frequently asked questions
Is 90 minutes enough for a nap?
At 90 minutes you're sleeping in full cycles rather than napping. Roughly every 90 minutes completes a cycle, and waking at a cycle boundary feels far better than waking mid-cycle.
Will this 90 minutes alarm work if I close the tab?
No. A browser alarm only runs while the page is open, so leave the tab open, keep the computer awake, and check the volume with the test button before you rely on it.
Does the timer start from when I press start or when I fall asleep?
From when you press start. If you usually take ten minutes to fall asleep, you'll sleep about ten minutes less than the alarm length — worth remembering for short naps, where those minutes are most of the nap.
What if I sleep through the alarm?
A browser alarm stops with one click, which a half-asleep brain manages easily. If you regularly sleep through naps or alarms, use one that can't be dismissed from where you're lying — WakeUpBroo for iPhone has no snooze and no dismiss button, and stops only when you type a rotating code from wakeupbroo.com/code on another device.
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Keep reading
Naps end. Mornings are the hard part.
If you can sleep through anything, the morning alarm needs to be one you can't silence from bed. WakeUpBroo has no snooze and no dismiss button — it stops only when you read a rotating code from this website on another device. Free to download, 7-day free trial.
Free on iPhone · Android in development