Oneirox Lab · Free instrument · No login
Sleep Cycle Calculator
Sleep cycles often average around 90 minutes, but their timing varies between people and across a night. Use a wake time or bedtime to explore planning estimates — not to identify your sleep stage or guarantee how waking will feel.
90
minutes
per cycle
14
min average
sleep onset
Math only — no account, no data sent anywhere. Uses a ~90-minute planning average and estimated sleep-onset latency; neither is a reading of your night.
Sleep includes NREM and REM, but their timing varies. These are planning estimates, not an indication of your current sleep stage or a guarantee about sleep inertia.
Science · not a lifehack
The ultradian rhythm, not a rule of thumb
Nathaniel Kleitman's basic rest-activity cycle (BRAC) and the classic Dement & Kleitman (1957) EEG studies established that human sleep alternates through NREM and REM in cycles averaging 90 minutes, four to six times a night. Cycle length is not perfectly fixed — it can range 70–110 minutes and shifts slightly across the night — so this calculator gives a small window of options rather than one rigid number.
Sleep inertia — grogginess, slowed reaction time, and disorientation right after waking — varies with sleep stage, sleep loss, timing, and the individual. A calculator built on an average cycle cannot identify your stage or guarantee less inertia; it offers planning intervals rather than a result about your own night.
This is a planning tool, not a Lab Search path. If a specific dream from one of these nights is still with you, open Lab Search for a mechanism-based interpretation — or add somatic detail first with the Sensory Dream Mapper.
Workflow
Three instruments, one lab
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01
Sleep Cycle Calculator
Plan bedtime or wake time around 90-minute cycle boundaries — before you sleep.
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02
Sensory Mapper (optional)
Map body sensations on waking — temperature, pressure, zones.
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03
Lab Search
Describe the dream. Receive SIGNAL · BODY · MORNING — one flagship reading, limited per day.
Know your cycles.
Now explore the rest of the Lab.
Free · No login · 400+ body-signal profiles · 26 dream mechanisms
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