Sleep Cycle Calculator (Best Bedtime & Wake Time)
Enter the time you want to wake up, or the time you go to bed, to get bedtime or wake-up times based on 90-minute sleep cycles. Set how long it takes you to fall asleep and see the times that help you wake up refreshed.
Input
Calculation direction
min
Result
Recommended bedtimes
Times that fall at the edge of a 90-minute sleep cycle, when waking up tends to feel easier.
9:46 PM
6 cycles · about 9 hr
Recommended
11:16 PM
5 cycles · about 7.5 hr
Recommended
12:46 AM
4 cycles · about 6 hr
2:16 AM
3 cycles · about 4.5 hr
How it works
- Sleep moves through light (REM) and deep (non-REM) stages in a cycle of about 90 minutes. This tool treats one cycle as 90 minutes. Waking at the end of a cycle, during lighter sleep, tends to feel more refreshing — these times are a guide based on that idea.
- In 'wake up at' mode, each suggested bedtime is the wake-up time minus (the time it takes to fall asleep + number of cycles × 90 minutes).
- In 'go to bed at' mode, each suggested wake-up time is your bedtime plus (the time it takes to fall asleep + number of cycles × 90 minutes).
- The 'time to fall asleep' (sleep latency) is how long it takes to drift off after getting into bed. The default of 14 minutes is a common average — adjust it to match yourself.
- Options cover 3 to 6 cycles (about 4.5 to 9 hours). Because adults generally need 7–9 hours of sleep, 5–6 cycles (about 7.5–9 hours) are highlighted as recommended.
- Cycle length and ideal sleep duration vary from person to person, so these times will not guarantee a refreshed wake-up. Use them as a general guide, and see a doctor if sleep problems persist.
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Sleep Cycle Calculator (Best Bedtime & Wake Time)