Sleep Cycle Calculator
⏰ Find Your Perfect Bedtime or Wake Time
Sleep cycles last ~90 minutes. Waking at the end of a cycle means you feel refreshed — not groggy. Use this tool to calculate the ideal times.
Sleep Quality Tracker
📊 Log Your Sleep
Track your nightly sleep to spot patterns, celebrate streaks, and identify what affects your rest.
The 4 Stages of Sleep
N1 — Light Sleep
Transition from wakefulness. Easily disrupted. Lasts only 1–7 minutes per cycle.
~5% of nightN2 — Core Sleep
Heart rate slows, body temperature drops. Memory consolidation begins. Sleep spindles appear.
~45% of nightN3 — Deep Sleep
Most restorative stage. Growth hormone released. Immune system repair. Hardest to wake from.
~25% of nightREM Sleep
Dreaming occurs. Emotional processing and creative problem-solving. Alcohol severely disrupts this.
~25% of nightThe Non-Negotiable Sleep Rules
Same Wake Time Daily
A consistent wake time — even weekends — is the single most powerful way to regulate your circadian rhythm.
Cool Room: 18–20°C
Your core body temperature must drop to initiate sleep. A room that's too warm is the most common sleep disruptor.
No Screens 45 Min Before
Blue light delays melatonin by 2–3 hours. Dim lights and stop all screens 45 minutes before your target sleep time.
No Caffeine After 2pm
Caffeine has a 5–6 hour half-life. A 3pm coffee still has half its stimulant effect at 9pm — delaying sleep onset significantly.
Avoid Alcohol as Sleep Aid
Alcohol sedates but reduces REM sleep by up to 40% and causes fragmented sleep in the second half of the night.
Bed = Sleep Only
Working or watching TV in bed trains your brain to associate the bedroom with alertness. Reserve it for sleep and sex only.