What Time Should I Wake Up?
Going to sleep now or at a set time? Enter your bedtime and the calculator adds the ~15 minutes to fall asleep, then counts 90-minute cycles to show the best times to set your alarm. Waking at the end of a cycle helps you feel alert instead of groggy.
Choose your mode, enter a time, and press Calculate to find optimal sleep times.
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Frequently asked questions
If I go to sleep now, what time should I wake up?+
Enter your bedtime above. The calculator adds ~15 minutes to fall asleep and then shows wake times at the end of 3, 4, 5 and 6 cycles. For a full night, target the 5- or 6-cycle option (7.5–9 hours).
What time should I wake up if I sleep at 11 PM?+
Falling asleep around 11:15 PM, good wake times are about 6:45 AM (5 cycles, 7.5 hours) or 8:15 AM (6 cycles, 9 hours). Enter 23:00 above to see all options.
How does the sleep calculator work?+
Sleep happens in roughly 90-minute cycles. Waking at the end of a cycle feels easier than being pulled out of one mid-way. The calculator takes your wake-up time (or bedtime), adds the ~15 minutes most people take to fall asleep, and counts whole 90-minute cycles to suggest the best times to sleep or wake.
How many hours of sleep do I need?+
Most adults need 7–9 hours — about 5 to 6 complete sleep cycles per night. Teenagers need 8–10 hours, school-age children 9–11, and younger children and babies more. Older adults often need slightly less, around 7–8 hours.
Why do I wake up tired even after 8 hours?+
Waking in the middle of a deep-sleep stage leaves you groggy (sleep inertia) even after a full night. Aligning your alarm to the end of a 90-minute cycle — what this calculator does — helps you wake more refreshed. Consistent sleep and wake times matter just as much.
Is the sleep calculator a medical tool?+
No — it's a general planning guide based on average 90-minute cycles, and individual cycles vary. If you have ongoing insomnia, loud snoring, daytime sleepiness, or chronic fatigue, speak to a doctor, as these can signal a treatable sleep disorder.