Sleep Calculator
Find the ideal bedtime or wake-up time based on 90-minute sleep cycles so you wake up feeling refreshed.
Recommended Bedtimes
Based on 90-minute sleep cycles — wake up between cycles to feel refreshed
💡 Tip: Most adults need 5–6 complete sleep cycles (7.5–9 hours). The highlighted times are ideal. You also need about 14 minutes to fall asleep.
Why Sleep in 90-Minute Cycles?
Sleep naturally occurs in 90-minute cycles, each moving through light sleep, deep sleep and REM. Waking mid-cycle leaves you groggy; waking at the end of a cycle feels natural. The sleep calculator on lifestylecalcfree.com calculates the exact times to set your alarm or go to bed.