Sleep cycle estimate
This tool uses 90 minutes per sleep cycle and adds 15 minutes as a rough time-to-fall-asleep estimate. It is a planning estimate, not medical advice.
Sleep Cycle Calculator
Choose a wake-up time and number of sleep cycles to estimate a bedtime.
How sleep cycles are estimated
The calculator counts backward from wake-up time in 90-minute blocks, then includes time to fall asleep. It is a planning shortcut, not a medical sleep assessment.
Example
Compare 4, 5 and 6 cycles for the same wake-up time. The difference shows how much earlier bedtime moves as cycles increase.
Common mistake
Do not treat 90 minutes as exact for everyone. Real sleep cycles vary, and sleep quality depends on more than timing.