Chronotype Calculator
Your chronotype is the biological expression of your circadian clock, whether you're wired for mornings, evenings, or somewhere between. This 7-question quiz places you on the Morningness-Eveningness spectrum and identifies your sleep type, optimal sleep window, and social jet lag score.
The four chronotype profiles
The Lion (15% of people) wakes naturally before 6:30am, hits peak energy before 10am, and is ready for bed by 9–10pm. Lions are chronobiologically aligned with most professional and social schedules, giving them a structural advantage that they rarely recognise because they've never known anything else.
The Bear (50%) roughly tracks the solar day, sleeps around 11pm–7am, and has a mid-morning peak with a 2–3pm dip. The majority of circadian research norms were established on bear-type subjects, making their schedule the implicit default.
The Wolf (30%) reaches peak alertness in the late afternoon and evening. Natural sleep onset is midnight to 1am; the 6:30am alarm is a biological assault. Wolves experience chronic social jet lag in a 9-to-5 world, accumulating sleep debt that compounds across the week.
The Dolphin (5%) sleeps lightly and briefly, often with irregular patterns. Sleep is disrupted by noise, temperature, and anxiety. Dolphins frequently identify as insomniacs even when sleep duration is technically adequate.
The genetics of sleep timing
Chronotype is 50% heritable. The PER3 gene (period-3 clock gene) has variants that shift the circadian period and correlate with morning vs. evening preference. A rare mutation in DEC2 allows some people to function on 6 hours. A mutation in CRY1 is associated with severe eveningness and delayed sleep phase syndrome. These are not preferences, they are biological programmes.
Related calculators
- Sleep Schedule Fixer — shift your clock earlier or later, day by day
- Melatonin Timing Calculator — when to take melatonin for your chronotype goal
- Sleep Quality Score — assess your overall sleep health
Frequently asked questions
What is a chronotype?
A chronotype is your biological tendency toward morning or evening activity, determined largely by genetics and the phase of your circadian clock. It's not just preference, it's reflected in measurable differences in melatonin onset, cortisol patterns, and core body temperature rhythms between individuals. About 15% of people are strongly morning-oriented (lions), 50% are intermediate (bears), 30% are evening-oriented (wolves), and 5% are light/irregular sleepers (dolphins).
Can your chronotype change?
Yes, chronotype changes predictably across the lifespan. Children are naturally early; teenagers shift dramatically later during puberty (by up to 2–3 hours, driven by hormonal changes in melatonin timing). Chronotype then gradually shifts back earlier through adulthood, becoming earliest in older age. Lifestyle interventions, consistent sleep timing, morning bright light, evening light avoidance, can shift your expressed chronotype by 30–60 minutes, though your genetic baseline is largely fixed.
What is social jet lag?
Social jet lag is the chronic circadian disruption caused by the misalignment between your biological clock and your social/work schedule. If your natural mid-sleep on free days is 4am but your alarm forces wake at 6:30am on workdays, you experience the equivalent of flying east across several time zones every Monday. Roenneberg et al. found that each hour of social jet lag is associated with a 33% increased odds of obesity, independent of sleep duration.
Is being a night owl a sleep disorder?
Being a wolf chronotype is a normal biological variation, not a disorder. Delayed Sleep Phase Syndrome (DSPS) is a clinical condition where the circadian delay is extreme (sleep onset after 2–3am) and causes significant functional impairment, but most wolves simply have a naturally later clock. The problem is not the chronotype itself but society's rigid scheduling, which structurally disadvantages evening types in a way that morning types never experience.
Based on Horne-Östberg MEQ and Roenneberg MCTQ methodology. For informational purposes only.