Sleep Calculator
Free tool
Sleep Calculator
Tell us when you need to wake up and we'll show the bedtimes that line up with full sleep cycles. Or see what time to set your alarm if you go to bed now.
How the calculator works
Sleep runs in cycles of roughly 90 minutes, though the length varies from person to person and through the night. Waking at the end of a cycle, not in the middle of deep sleep, tends to feel easier. The calculator counts back (or forward) in 90-minute cycles and adds about 15 minutes to fall asleep.
The CDC recommends at least 7 hours of sleep a night for adults. That's why 5 or 6 cycles (7.5 or 9 hours) are the times we highlight.
Common questions
What if I wake up before my alarm?
That's normal. Cycle length shifts with age, stress and how tired you are, so treat these times as a starting point and adjust by 15–30 minutes until mornings feel easier.
Does a consistent schedule matter?
Yes. Going to bed and waking up at about the same time every day, weekends included, is one of the simplest sleep habits to start with.
Where do supplements fit in?
They come after the basics: a regular schedule, a dark and cool room, and less screen time late at night. Read our guide to what actually helps sleep.
Wind-down picks
Magnesium Citrate Gummies200 mg per 2-gummy serving$17.99 Melatonin 5mg Sleep GummiesVegan · 60ct$11.99 The Deep Sleep DuoBundle$29.99- Centers for Disease Control and Prevention. About Sleep: How much sleep do I need?
- National Institute of Neurological Disorders and Stroke. Brain Basics: Understanding Sleep.
This tool shares general information. It isn't medical advice. If you regularly have trouble sleeping, talk to your healthcare provider. *These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
