The tests
- The sleep calculator takes a bedtime or a wake-up time and shows which times fall at the end of a sleep cycle, with 7–9 hours highlighted.
- The chronotype test asks about your natural sleep and energy rhythm and tells you whether you lean toward morning lark, night owl or in between.
Your body clock
Everyone has an internal clock that shapes when you feel alert and when you feel sleepy. Some people naturally wake early and fade in the evening, others come alive late at night. This preference is called your chronotype, and it shifts with age. Knowing it can help you plan demanding work for your best hours and choose a bedtime you can actually keep.
Know the limits
The sleep calculator works with typical cycle lengths, not your own, and our chronotype questionnaire is an original, non-normed self-check. If you often struggle to fall asleep, wake up unrefreshed, snore loudly or feel very sleepy during the day, talk to a doctor; these can be signs of a sleep disorder that a calculator or questionnaire cannot detect.