- Choose whether you want to calculate bedtime or wake-up time.
- Set your target time and how long it usually takes you to fall asleep.
- Click Calculate to see 1–6 cycle options (1.5 to 9 hours of sleep).
Sleep Cycle Calculator
Calculate when to wake up or go to bed based on 90-minute sleep cycles.
What do you want to calculate?
Choose whether you have a wake-up time or a bedtime in mind.
Time
Your target wake-up time or bedtime.
Time to fall asleep (minutes)
Average time to fall asleep; about 14 minutes for most people.
Result
Set your time and click Calculate.
How to Use This Tool
Learn More About Sleep Cycle Calculator
What is a sleep cycle?
A full cycle includes light sleep, deep sleep, and REM and usually lasts about 90 minutes. Waking between cycles (rather than in deep sleep) can help you feel less groggy.
How is the time calculated?
The tool adds or subtracts your fall-asleep time and then steps in 90-minute increments to list 1–6 full cycles.
About
The Sleep Cycle Calculator uses 90-minute sleep cycles to suggest bedtimes or wake-up times so you wake between cycles.
Examples
Calculate Bedtime for an Early Morning
Find out the best times to go to sleep if you need to wake up at 6:00 AM for work or school.
Input
The 'Wake Up At' option is selected and the time is set to 6:00 AM.
Output
A list of suggested bedtimes, such as 8:46 PM (6 cycles), 10:16 PM (5 cycles), or 11:46 PM (4 cycles), which account for the average time to fall asleep.
Calculate Wake-up Times for a Late Night
Determine the optimal times to set your alarm if you plan to go to bed at 1:00 AM.
Input
The 'Go to Bed At' option is selected and the time is set to 1:00 AM.
Output
A list of suggested wake-up times, such as 8:44 AM (5 cycles) or 10:14 AM (6 cycles), based on completing full 90-minute sleep cycles.
Find the Perfect Nap Length
Calculate the ideal wake-up time after a short nap to avoid feeling groggy.
Input
The 'Go to Bed At' option is selected with the current time (e.g., 2:00 PM) entered.
Output
Suggested wake-up times corresponding to one or two full sleep cycles, such as 3:44 PM (one 90-minute cycle plus the 14-minute average to fall asleep).
Use Cases
- Planning when to go to bed for a set alarm.
- Choosing when to set the alarm for a target bedtime.
- Understanding how many cycles you get for a given sleep window.