Chronotype Bedtime Calculator

About this calculator

A chronotype describes whether your body's internal clock naturally runs earlier (‘lark,’ or morning type) or later (‘owl,’ or evening type), and chronobiologists commonly summarize it with the sleep midpoint — the point exactly halfway between the time you fall asleep and the time you wake up on a day with no alarm. Building a schedule around that midpoint, rather than an arbitrary bedtime, keeps sleep and wake times aligned with the circadian rhythm your body actually runs on.

This matters because forcing an evening-type person onto an early bedtime, or a morning-type person into a late one, tends to produce social jet lag: the same mismatch between body clock and schedule that causes jet lag from travel, but caused by a daily routine instead. Sleep researchers use midpoint-based scheduling, popularized by tools like the Munich ChronoType Questionnaire, to design more realistic sleep advice than a one-size-fits-all ‘go to bed by 10pm’ rule.

Pick your chronotype and how much sleep you need, and the calculator works back from your natural sleep midpoint to suggest a bedtime and wake time that fit your body clock rather than fighting it.