Sleep Calculator

Wake up refreshed
every morning.

Sleep happens in 90-minute cycles. Hit one cleanly and you wake up energized instead of groggy.

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Enter when you need to fall asleep
💤 Sleep Cycle Options
Sleep science facts
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90-minute sleep cycles. Each cycle goes through light sleep, deep sleep, and REM. Waking mid-cycle causes sleep inertia (that groggy, disoriented feeling).
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Most adults need 5-6 full cycles (7.5-9 hours). Getting 6 cycles in is rare but powerful. Even 4 cycles is better than waking mid-cycle after 8 hours.
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Consistency beats duration. Going to sleep and waking at the same time every day (including weekends) is the single most impactful sleep habit.