Four times, two minutes. You get four figures about yourself, set against what studies measure. No advice, and nothing is stored: everything is computed on your screen.
The tool computes your average sleep duration over the week, weighting five work days and two free days. It then finds the midpoint of each night: the gap between the midpoint of work nights and that of free nights is social jetlag.
Chronotype is estimated from the midpoint of your free nights, corrected for the sleep debt built up during the week, following the Munich Chronotype Questionnaire (MCTQ) method developed by Till Roenneberg's team.
The American sleep societies (AASM and SRS) recommend at least 7 hours a night for adults. The National Sleep Foundation publishes a range of 7 to 9 hours between 18 and 64, and 7 to 8 hours after 65.
It is the gap between the clock of your work days and that of your free days, measured between the midpoints of your nights. One hour of gap is like changing time zones every weekend. In large observational studies it is associated with a higher body mass index, without proof of cause.
The midpoint of your sleep on days without an alarm, corrected for your weekly debt, places your chronotype. It depends on genetics, age, sex and environment, light in particular, and gets later during adolescence.
Sleeping more on free days reduces how tired you feel. But in a controlled trial published in 2019, weekend recovery sleep did not undo the metabolic effects of a week of short nights.
No. Everything is computed in your browser and nothing is sent to our servers. If you ask for it, your results can be kept on your device, in your summary, and deleted at any time.