Hubs
Sleep Hub
Bedtimes, sleep debt, jet lag, children's sleep — and the clinical work on chronic insomnia: CBT-I, sleep restriction, sleep diaries.
Start here
Sleep topics fall into four themes. Each one gathers the calculator that fits it and the guides that explain it — start with the one you are dealing with.
Daily timing and rhythm
Work out when to sleep and when to wake, and why your body clock prefers those hours.
- Sleep CalculatorFind the best time to wake up or go to bed using sleep cycle science.
- Caffeine Cutoff CalculatorSee how much of a caffeine dose is left in the body at bedtime, the latest time you can have it and stay at or below the level you choose, and the hour it falls to that level.
- Chronotype CalculatorFind your chronotype and estimate social jet lag based on your sleep schedule.
- Sleep Cycles and StagesUnderstand the sleep cycle, REM and deep sleep stages, and how cycle timing affects sleep quality.
- Chronotype and Circadian RhythmUnderstand chronotypes, circadian rhythm, social jet lag, and how schedule alignment affects sleep quality.
- Light and Melatonin TimingHow daily light timing works around your own clock, and where melatonin fits as the body's dark signal.
Recovery and travel
Recover from lost sleep, and shift your schedule across time zones without guesswork.
- Sleep Debt CalculatorCalculate your total sleep debt and find out how long recovery takes.
- Nap CalculatorWork out how long to nap and when to wake: a power nap, or one to three full sleep cycles of about 90 minutes each.
- Jet Lag CalculatorPlan your sleep schedule for time zone travel and reduce jet lag.
- Sleep Debt RecoveryLearn how sleep debt works, how to estimate your shortfall, and how to recover with gradual pacing.
- Jet Lag Sleep PlanningPlan your sleep for time zone travel with light exposure guidelines and gradual schedule shifts.
Insomnia and CBT-I
Understand CBT-I and run a sleep-restriction plan safely, week by week.
- Sleep Restriction Therapy CalculatorCalculate your sleep window using sleep restriction therapy (SRT) and CBT-I principles.
- What Is CBT-I?Learn what Cognitive Behavioral Therapy for Insomnia (CBT-I) is, its core components, and why it is the first-line treatment for chronic insomnia.
- Sleep Restriction Therapy ExplainedHow sleep restriction therapy works for insomnia: time in bed, sleep efficiency, fixed wake time, safety floors, and weekly adjustments.
- CBT-I vs Sleep HygieneWhy CBT-I is more effective than sleep hygiene alone for chronic insomnia, and how both approaches differ.
- CBT-I Plan: How the Pieces Fit TogetherHow sleep diary, stimulus control, sleep restriction, cognitive techniques, and relaxation fit into a structured CBT-I program.
- Sleep Diary and Sleep EfficiencyHow to track your sleep with a sleep diary and calculate sleep efficiency for CBT-I sleep restriction therapy.
- How to Adjust Your Sleep Window Week by WeekHow to adjust your sleep window each week based on sleep efficiency during CBT-I sleep restriction therapy.
- Sleep Compression vs Sleep RestrictionThe difference between sleep compression and sleep restriction therapy, and when a gradual approach may be more appropriate.
- Stimulus Control TherapyHow stimulus control therapy strengthens the bed-sleep connection and helps treat chronic insomnia.
- Cognitive Techniques for InsomniaCognitive restructuring techniques from CBT-I: managing worry time, catastrophic thoughts, and sleep performance anxiety.
- When Sleep Restriction May Not Be AppropriateMedical and safety considerations before trying sleep restriction therapy: bipolar disorder, seizure risk, sleep apnea, and other contraindications.
Family sleep
Find age-based sleep windows for children and teenagers, and the reasons behind them.
Sleep calculators
Sleep Calculator
Find the best time to wake up or go to bed using sleep cycle science.
Caffeine Cutoff Calculator
See how much of a caffeine dose is left in the body at bedtime, the latest time you can have it and stay at or below the level you choose, and the hour it falls to that level.
Sleep Debt Calculator
Calculate your total sleep debt and find out how long recovery takes.
Nap Calculator
Work out how long to nap and when to wake: a power nap, or one to three full sleep cycles of about 90 minutes each.
Chronotype Calculator
Find your chronotype and estimate social jet lag based on your sleep schedule.
Jet Lag Calculator
Plan your sleep schedule for time zone travel and reduce jet lag.
Kids Sleep Calculator
Find age-based sleep recommendations for children and teenagers.
Sleep Restriction Therapy Calculator
Calculate your sleep window using sleep restriction therapy (SRT) and CBT-I principles.
Sleep Hub FAQ
Is this Sleep hub only for people with insomnia?
No — it covers both halves of sleep. Everyday timing and recovery: a bedtime or a wake time for tonight, the sleep debt you are carrying, jet lag after a flight, a child's schedule. And the clinical work on chronic insomnia: CBT-I (Cognitive Behavioral Therapy for Insomnia), a structured, evidence-based program and the first-line recommended treatment for chronic insomnia, whose key techniques — sleep restriction, sleep efficiency tracking, stimulus control, a sleep diary — the tools and guides here support.
How does sleep restriction fit into CBT-I?
Sleep restriction therapy (SRT) is a core behavioral component of CBT-I. It intentionally narrows the time in bed to match actual sleep duration, then gradually increases it as sleep efficiency improves. It is not about chronic sleep deprivation — the window is adjusted weekly based on efficiency. SRT should only be done under the guidance of a qualified clinician when possible, and the calculator provides educational estimates to support the process.
When should I seek medical guidance instead of using these tools?
These tools provide educational estimates only. If you have persistent insomnia, severe daytime sleepiness, untreated sleep apnea, bipolar disorder, seizure risk, or work in a safety-critical role, consult a qualified clinician before changing your sleep schedule. Sleep restriction therapy may not be appropriate for everyone, and a clinician can help determine the right approach for your situation.
Sources and methodology
Sleep-cycle timing is based on average adult sleep cycle duration. Sleep restriction therapy estimates follow CBT-I sleep-window principles and conservative safety floors. References include the American Academy of Sleep Medicine, CDC sleep guidance, and NIH NHLBI sleep health resources.
These calculators provide educational estimates only. If you have persistent insomnia, severe daytime sleepiness, untreated sleep apnea, bipolar disorder, seizure risk, or safety-critical work, consult a qualified clinician before changing your sleep schedule.