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Discover your chronotype and optimal daily schedule.

Answer 6 science-based questions adapted from the Munich Chronotype Questionnaire (MCTQ) to find out whether you are a Morning Lark, Intermediate, or Night Owl — and get a personalized schedule.

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Chronotype — Sleep Type & Optimal Schedule
MCTQ-based questionnaire · 6 questions · personalized daily clock
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Your questionnaire

Four times and one checkbox. Your chronotype comes from when you actually sleep, not from how you rate yourself.

If you do, the sleep-debt correction cannot be applied — an alarm cuts the night short, so there is no catch-up sleep to correct for.
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Your chronotype

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Complete the questionnaire above

How it's calculated

MCTQ scoring: from sleep timing to chronotype

The Chronotype Calculator scores your biological clock using six questions adapted from the Munich Chronotype Questionnaire (MCTQ). The key metric is your Mid-Sleep on Free days (MSF) — the midpoint between your natural sleep onset and natural wake time. MSF below 3:30 AM = Morning type; 3:30–5:00 AM = Intermediate; above 5:00 AM = Evening type. The questionnaire adds four behavioral and subjective items (morning alertness, daily peak, ease of early rising, sleep need) to refine the classification.

The MCTQ, developed by Prof. Till Roenneberg at LMU Munich, is validated on hundreds of thousands of participants. Free-day sleep timing is used because it is largely free from social constraints, revealing the true internal clock. The score from questions 3–6 shifts the boundary slightly to capture phenotypic nuances beyond timing alone.

MSF = sleep_onset + sleep_duration / 2
Score = MSF_points + alertness_pts + peak_pts + early_pts
Morning ≤ 5 · Intermediate 6–9 · Evening ≥ 10
  1. 1
    Calculate sleep duration on free days
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  2. 2
    Calculate Mid-Sleep on Free days (MSF)
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  3. 3
    Map MSF to base score (0–8 points)
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  4. 4
    Add behavioral questionnaire points (0–8)
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  5. 5
    Classify chronotype from total score
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Understand the terms

Chronotype
An individual's natural tendency to sleep and be active at certain times of day, driven primarily by genetics and the circadian clock.
Circadian rhythm
The body's internal ~24-hour biological clock that regulates sleep, hormones, body temperature and metabolism. Governed by the suprachiasmatic nucleus (SCN) in the hypothalamus.
Social jetlag
The chronic discrepancy between the biological clock (chronotype) and the socially imposed schedule (work, school). Measured as the difference in mid-sleep time between free days and work days.
MCTQ (Munich Chronotype Questionnaire)
A validated questionnaire developed by Till Roenneberg measuring chronotype via self-reported sleep timing on free and work days.
Melatonin
The "darkness hormone" secreted by the pineal gland, signaling the body to prepare for sleep. Its onset time (DLMO) is a reliable biomarker of circadian phase.
See the full glossary →

🔢 Worked example

Asleep 23:00 to 07:00 on workdays (8 h) and 00:00 to 09:00 on free days (9 h), five workdays. Weekly average sleep = (8 × 5 + 9 × 2) ÷ 7 = 8.29 h. Mid-sleep on free days = 00:00 + 4.5 h = 04:30. Correcting the 0.71 h of catch-up sleep gives MSFsc 04:09 — an intermediate chronotype.

Disclaimer: estimation tool for informational and planning purposes only. This calculator implements the MCTQ chronotype formula (Roenneberg et al.) and does not constitute a clinical diagnosis. Results may differ from a formal sleep study or laboratory chronotype assessment. Consult a sleep specialist or physician if you have concerns about sleep disorders. Does not replace professional medical advice.

Frequently asked questions — Chronotype

What is a chronotype?
A chronotype describes your natural tendency to sleep and be active at certain times of day. It is largely determined by genetics and your circadian rhythm — the internal ~24-hour biological clock. The main chronotypes are Morning (lark), Intermediate, and Evening (owl). Chronotype shifts across the lifespan: children tend to be morning types, adolescents shift strongly toward evening, and adults gradually shift back after age 20–30.
What is the MCTQ (Munich Chronotype Questionnaire)?
The MCTQ was developed by Prof. Till Roenneberg at Ludwig Maximilian University of Munich and validated on hundreds of thousands of participants. It measures chronotype by asking about sleep timing on free days — days without social obligations — because free-day sleep most accurately reflects the internal clock without the masking effect of alarms or schedules. The key metric is the Mid-Sleep on Free days (MSF).
Can I change my chronotype?
Chronotype is substantially genetic and stable, but it can be partially shifted by timed light exposure, meal timing and exercise. Morning bright light (sunlight or a 10,000-lux lamp) advances the clock; bright light in the evening delays it. For most people, a 1–2 hour adjustment is achievable, but fully overriding a strong evening chronotype is difficult. Consistency in sleep and wake times also matters greatly.
What is social jetlag?
Social jetlag is the discrepancy between your biological clock and your socially required schedule (work or school hours). It is calculated as the difference in mid-sleep time between free days and work days. For example, if your natural mid-sleep is 4 AM but work requires you to sleep with a mid-point of 2 AM, you have 2 hours of social jetlag. Chronic social jetlag is associated with poorer metabolic health, increased obesity risk, impaired mood and reduced cognitive performance.
What time should a night owl go to sleep?
A strong evening chronotype naturally feels sleepy between midnight and 2 AM and wakes naturally around 8–10 AM. To minimize social jetlag while still getting 7–9 hours, evening types should maintain a consistent sleep schedule even on weekends, get bright morning light exposure as early as possible to advance the clock, avoid bright artificial light and screens after 9 PM, and keep the bedroom cool and dark.
Are my results saved? Do I need an account?
No account or sign-up needed. Every calculation is saved automatically in your own browser, and you can also pin a result with the save button. Nothing is sent to any server: the data stays on your device and can be erased at any time with the clear button.
How do I track my progress over time?
From the fourth entry onward a “View comparison chart” button appears, opening a line chart with every entry in time order plus an indicator panel: total change, average per entry, lowest and highest value and the period covered. You can also export the history as CSV.

📚 Learn more — official sources

🏛️ Organization rOpenSci mctq — the MSFsc formula, documented Open documentation of the exact equation this page computes, including the two conditions most implementations miss: an alarm on free days leaves MSFsc undefined, and without oversleep there is no correction to apply. Implements Roenneberg et al. See the formula → 🔬 Study Roenneberg et al. — Social jetlag and obesity (2012) Landmark study linking social jetlag (mismatch between chronotype and work schedule) to increased BMI, published in Current Biology. See on PubMed Central → 🏛️ Organization NIH — Sleep Deprivation and Deficiency National Heart, Lung, and Blood Institute overview of sleep science, healthy sleep guidelines, and the effects of sleep deprivation on health. See official source → 🏛️ Organization CDC — Sleep and Sleep Disorders U.S. Centers for Disease Control and Prevention resources on sleep health, recommended sleep duration by age, and sleep disorder information. See official source → 🔬 Study Roenneberg et al. — Epidemiology of the human circadian clock (2007) Large-scale MCTQ study characterizing chronotype distribution across 55,000 participants, showing the age- and sex-related shifts in sleep timing. See on PubMed →

🔄 Page last reviewed: July 2026. Laws and standards cited keep their original publication year; the date above is when the content and the calculation were reviewed.

About the Chronotype Calculator

Your chronotype is your biological preference for when to sleep and be active. Research by Till Roenneberg and colleagues at LMU Munich, and popularized by Matthew Walker's Why We Sleep, has shown that chronotype is largely genetic, affects about 40% of the population as evening types, and has profound implications for health, performance and wellbeing.

This calculator uses six questions adapted from the Munich Chronotype Questionnaire (MCTQ) methodology to estimate your chronotype and generate a personalized daily schedule. The core metric — Mid-Sleep on Free days (MSF) — is the most accurate self-report proxy for the internal circadian clock, validated against melatonin assays (DLMO) in research settings.

By Vinicius Fonseca · Formulas checked against scientific sources · Updated Jul 2026 · How we calculate →