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Wake me up in 8 hours
The alarm below is already set to 8 hours from now — press Set alarm and leave this tab open. Below, what a 8h sleep actually does, and how to come out of it well.
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WakeUpBroo
iPhone alarm
No snooze. To stop it, you get up: type a code on your laptop, or scan an item in another room.
Download5 to 8 hours: that's a night's sleep, not a nap
At this length you aren't napping — you're choosing how much of a night you get. Most adults need seven to nine hours, so eight hours from now is a full night for most people and five is a short one. Both work out reasonably against the 90-minute cycle: allow about 15 minutes to fall asleep and five hours lands just after your third cycle ends, eight hours just after your fifth. Neither drags you out of the middle of deep sleep, which is what makes some alarms feel like being hit by a truck.
Remember the clock starts when you press start, not when you fall asleep. If you're lying awake for half an hour, “8 hours” is really seven and a half — still fine. “5 hours” becomes four and a half, and that's a night you'll feel tomorrow. Short nights now and then are survivable; a week of them builds a sleep debt that no single lie-in pays back.
The bigger risk at this length is the alarm itself. After a real night's sleep, the alarm is competing with the deepest part of your rhythm — the morning you most need to wake is the one you're likeliest to sleep through. If it's an early flight or a shift, plan the whole night properly with the sleep calculator, and use an alarm you can't switch off from the pillow.
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 finish a wake-up task, by default typing 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 5 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 8 hours of sleep enough?
For most adults, yes — seven to nine hours is the usual need, and 8 hours from now leaves about 15 minutes less than that asleep once you allow time to drift off. It also lands close to the end of a 90-minute cycle, so waking should feel easier than the hours alone suggest.
Will this 8 hours 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 finish a wake-up task, by default typing 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 finish a wake-up task, by default reading a rotating code from this website on another device. Free to download, 3-day free trial.
Free to download on iPhone · Android in development