Find your optimal sleep and wake-up times based on 90-minute sleep cycles. Wake up refreshed and energized every morning.
What time do you want to wake up or go to bed?
Follow these simple steps to find your optimal sleep schedule and wake up feeling refreshed
Select whether you know your desired wake-up time or bedtime. Enter the time in the calculator.
Our calculator computes several recommended times based on complete 90-minute sleep cycles.
Choose the option that best fits your schedule to wake up feeling refreshed and energized.
Understand the science behind sleep cycles and why they matter for your health and productivity
Healthy sleep consists of repeating 90-minute cycles that include light sleep, deep sleep, and REM sleep. Completing full cycles helps avoid waking during deep sleep, which causes grogginess.
REM (Rapid Eye Movement) sleep is crucial for memory consolidation, learning, and mood regulation. Most REM sleep occurs in the later cycles of the night.
Most adults need 5-6 complete sleep cycles per night (7.5-9 hours) to feel fully rested. Interrupted cycles can lead to sleep debt and reduced cognitive function.
Join thousands of people who have improved their sleep with our calculator
Find answers to common questions about sleep cycles and our calculator
The 90-minute sleep cycle rule suggests that we sleep in cycles of approximately 90 minutes, moving through light sleep, deep sleep, and REM sleep. Waking up at the end of a cycle (during light sleep) helps you feel more refreshed.
Sleep Calculator uses the 90-minute sleep cycle principle to calculate optimal bedtimes or wake-up times. It adds or subtracts 90-minute intervals from your desired time, accounting for the average 15 minutes it takes to fall asleep.
Most adults need 5-6 complete sleep cycles per night, which equals 7.5 to 9 hours of sleep. This allows for sufficient deep sleep and REM sleep for optimal cognitive function and physical recovery.
For a 7 AM wake-up, ideal bedtimes would be: 9:45 PM (6 cycles), 11:15 PM (5 cycles), or 12:45 AM (4 cycles). Choose based on how many hours of sleep you need.
You may be waking up during a deep sleep phase. Using Sleep Calculator helps you time your sleep to wake up during lighter sleep stages, reducing grogginess.