Sleep Smarter.
Wake Refreshed.
Plan a bedtime that gives you enough time to sleep. The calculator uses approximate 90-minute cycles as a guide, not a prediction of your sleep stages.
Sleep Cycle Calculator
What time do you need to wake up?
7:00 AM
Go to bed at...
Most adults should plan for at least 7 hours of sleep. Shorter options are shown only as planning estimates. Sleep cycles vary, so a 90-minute calculation cannot predict your actual sleep stages or guarantee how you will feel on waking.
Illustrative sleep stages — 5 cycles
This diagram is illustrative; the tool does not measure sleep stages.
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Get My Free Sleep TipsHow Sleep Cycles Work
Every night, your body cycles through distinct stages of sleep in roughly 90-minute intervals. A complete cycle moves from light sleep (N1, N2) into deep sleep (N3) and then into REM (rapid eye movement) sleep, where most dreaming occurs.
Sleep stages and cycle lengths vary throughout the night. This calculator estimates schedule options from a 90-minute average; it cannot tell when you will enter or leave a particular stage. Most adults should first allow at least seven hours of sleep.
Most adults complete 4 to 6 sleep cycles per night. The early cycles are rich in deep sleep (critical for physical recovery), while later cycles contain more REM sleep (essential for memory consolidation and emotional regulation).
The 90-minute cycle is an average. Use these times as a starting point for a consistent routine, then adjust based on how much sleep you get and how you feel during the day.
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Medical Disclaimer
The information provided by Sleep Stack is for educational and informational purposes only and is not intended as medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or sleep disorder. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
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