Mode

min

How long do you usually need to fall asleep? Start value 15 minutes (assumption).

Optimal bedtime

23:15

To wake up rested at 07:00, it is best to fall asleep at 23:15: 5 sleep cycles (7 h 30 min) plus 15 min to fall asleep.

Night from 23:15 to 07:00: 15 minutes to fall asleep, then 5 sleep cycles of 90 minutes.

All options (3–6 sleep cycles)

  • 21:45

    6 cycles · 9 h

  • 23:15

    5 cycles · 7 h 30 min

  • 00:45

    4 cycles · 6 h

  • 02:15

    3 cycles · 4 h 30 min

Average sleep duration by age

Children (6–12 years)
about 9 h
Teenagers
about 8 h
around 40 years
about 7 h
55–60 years
about 6.5 h
healthy 80-year-olds
about 6 h

Rough guidance, not a sleep diagnosis. A sleep cycle normally lasts 90 to 110 minutes – the calculator assumes 90 minutes. The sleep durations are averages; what matters is how rested you feel during the day. Source: gesundheitsinformation.de (IQWiG)

How this was calculated
Bedtime = wake-up time − cycles × 90 min − 15 min
07:00 − 5 × 90 − 15 = 23:15

Sleep Calculator by Rechnerzentrale(opens in a new tab)