The Sleep Cycle Calculator helps you find the best times to wake up or go to bed so you complete full 90-minute sleep cycles, waking up naturally between cycles when you feel most refreshed.
A typical sleep cycle lasts approximately 90 minutes and includes light sleep, deep sleep, and REM sleep. Waking up at the end of a cycle — rather than in the middle of deep sleep — leaves you feeling more alert and rested.
Enter either your planned bed time or your required wake time, along with how long it typically takes you to fall asleep. The calculator will show you the ideal times for the opposite, covering 1 through 6 complete sleep cycles.
The average person takes about 10–20 minutes to fall asleep. Adjust this value to match your own experience. This offset is added to your bed time before cycles are counted, so your results reflect actual sleep time rather than time in bed.
Most adults need 5–6 complete cycles (7.5–9 hours) of sleep per night. Fewer than 4 cycles (6 hours) is generally considered insufficient for long-term health. The calculator highlights the recommended range to help you choose the best option.