Find optimal bedtimes based on 90-minute sleep cycle intervals.
Calculator Parameters
Enter details and click calculate to view the results instantly.
Calculation Examples
Scenario Inputs
Output Result
wakeTime : 07: 00
Suggested Bedtimes: 22:00 or 23:30
About Sleep Calculator
Sleep Cycle Target Calculator. Find optimal bedtimes based on 90-minute sleep cycle intervals. Starlightopia provides this tool completely free and online, optimized for instant, accurate computations.
Technical Specifications
CategoryUnit & Everyday
Target ValueOptimal Bedtimes
Inputs Required (1)
Desired Wake Up Time (e.g. 07:00) (text)
Frequently Asked Questions
How long does a normal human sleep cycle last?
A standard human sleep cycle lasts about 90 minutes, moving through light sleep, deep sleep, and REM stages.
How many sleep cycles should I target each night?
Targeting 5 to 6 full sleep cycles per night provides 7.5 to 9 hours of restorative rest.
Why do I feel exhausted even after getting 8 hours of sleep?
Waking up in the middle of a deep sleep cycle rather than at the end of a 90-minute interval often leaves you feeling groggy.
What does sleep latency mean?
Sleep latency is the time it takes you to fall asleep after getting into bed, averaging about 14 minutes for most healthy adults.
How does blue light exposure affect circadian sleep cycles?
Blue light from digital screens suppresses the body's melatonin production, which can delay sleep onset and disrupt your internal clock.