Wake Refreshed,
Not Groggy.
Waking in the middle of a 90-minute sleep cycle triggers heavy sleep inertia. Calculate exact bedtime and wake alarms that align with your natural brainwave transitions, plus model your personal caffeine curfew.
90-Minute Brain Cycles
Sleep naturally cycles between light, deep, and REM sleep every ~90 minutes. Timing alarms to boundaries makes waking effortless.
5-Hour Caffeine Half-Life
A 200mg coffee at 4 PM leaves 50mg active at 2 AM. We model exact pharmacokinetic decay curves.
The 20-Minute Power Nap
Why 45-minute naps leave you exhausted: avoid falling into deep delta wave sleep during midday rests.
Sleep Architecture Engines
Evidence-based calculators to optimize your rest and cognitive recovery.
Bedtime Calculator
Bedtimes matched to whole sleep cycles from your wake time — with fall-asleep time and cycle length you can tune.
Caffeine Curfew Calculator
When to stop caffeine for your bedtime — half-life math on your actual intake, not folklore rules of thumb.
Sleep Debt Calculator
Total your sleep debt across the week — and the realistic payback schedule that clears it without wrecking your rhythm.
Nap Calculator
Nap lengths that refresh instead of grog — 20-minute power naps, 90-minute full cycles, and the ideal window.
The Architecture of Sleep
Explore adenosine accumulation, REM rebound, and sleep hygiene protocols.
What Actually Happens in a 90-Minute Sleep Cycle
Light sleep, deep sleep, REM — the nightly assembly line your brain runs, why the order matters, and how to wake at the right end of it.
Caffeine and Sleep: The Half-Life Math Nobody Does
A 3 pm coffee is a half-espresso at bedtime. The exponential decay, individual half-lives from 2 to 10 hours, and how to find your own curfew.
Sleep Debt Is Real — And You Can't Repay It All At Once
Two weeks of 6-hour nights impair you like a full night without sleep — while feeling fine. The lab evidence, and the recovery schedule that actually works.