Sleep Calculator
Calculate the optimal bedtime or wake-up time based on sleep cycles. With clear explanations, recommendations and comparison values.
To wake up optimally rested:
21:46
6 Sleep Cycles
9 hours of sleep
Recommended23:16
5 Sleep Cycles
7.5 hours of sleep
Recommended00:46
4 Sleep Cycles
6 hours of sleep
Note: A sleep cycle lasts approximately 90 minutes.
- A sleep cycle lasts approx. 90 minutes
- 5-6 cycles are optimal (7.5 - 9 hours)
- Waking between cycles feels more refreshing
- Approx. 14 minutes falling asleep time included
Note: These calculations are for informational purposes only and do not replace professional tax or financial advice. All information without guarantee.
Frequently Asked Questions
How much sleep do adults need?
Adults typically need 7-9 hours of sleep per night. Sleep cycles last about 90 minutes, so planning sleep in multiples of 90 minutes (e.g., 7.5 hours) can help you wake feeling refreshed.
What time should I go to bed?
Count back from your wake time in 90-minute sleep cycles. For a 6:30 AM alarm, ideal bedtimes are 9:00 PM (6 cycles), 10:30 PM (5 cycles), or midnight (4.5 cycles), plus 15 minutes to fall asleep.
What is the Sleep Calculator?
The sleep calculator computes optimal sleep and wake times based on sleep cycles of approximately 90 minutes.
How does the Sleep Calculator work?
Enter your desired wake-up time or bedtime. The calculator computes optimal times in 90-minute cycles so you wake at the end of a cycle and feel rested. The time to fall asleep (approx. 15 min) is factored in.
Key Data and Facts
Sleep cycle: approx. 90 minutes. Recommended cycles: 5-6 per night (7.5-9 hours). Recommended sleep for adults: 7-9 hours. Average time to fall asleep: 15 minutes.
Step-by-Step Guide
How to calculate optimale Schlafzeiten step by step: 1. Aufwachzeit oder Einschlafzeit enter: choose Sie, ob Sie die optimale Einschlafzeit oder Aufwachzeit calculate moechten. 2. Einschlafzeit beruecksichtigen: Der Rechner addiert ca. 15 Minuten, die durchschnittlich zum Einschlafen benoetigt werden. 3. Schlafzyklen verstehen: Ein Schlafzyklus dauert ca. 90 Minuten und durchlaeuft Leichtschlaf, Tiefschlaf und REM-Phase. Am Ende eines Zyklus wachen Sie leichter und erholter auf. 4. Empfohlene Zeiten ablesen: Der Rechner schlaegt 4-6 Zyklen vor: 4 Zyklen = 6 hours, 5 Zyklen = 7,5 hours (ideal fuer die meisten Erwachsenen), 6 Zyklen = 9 hours. 5. Beispiel: Aufwachzeit 6:30 Uhr. Optimale Einschlafzeiten: 23:00 Uhr (5 Zyklen), 21:30 Uhr (6 Zyklen) oder 00:30 Uhr (4 Zyklen). Minus 15 Min. Einschlafzeit: Ins Bett gehen um 22:45, 21:15 oder 00:15 Uhr.
Calculation Example
Aufwachzeit 6:30 Uhr, 5 Schlafzyklen gewuenscht: 5 x 90 Min. = 7,5 hours. Einschlafzeit: 23:00 Uhr. Zubettgehzeit (minus 15 Min.): 22:45 Uhr.
Related Calculators
BMI Calculator
Calculate your Body Mass Index (BMI) and find out if your weight is in the normal range. According to WHO classification.
Calorie Calculator
Calculate your daily calorie needs. Basal metabolic rate and total needs using Harris-Benedict and Mifflin-St Jeor formulas.
Ovulation Calculator
Calculate your fertile days and ovulation. For natural family planning. Scientifically based, free, no registration required.
Due Date Calculator
Calculate the expected due date of your baby using Naegele's rule. With clear explanations, recommendations and comparison values.