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Free sleep cycle calculator. Find the best bedtime or wake-up time using 90-minute sleep cycles so you feel more rested.
Pick a mode and calculate.
Sleep usually rotates through light, deep, and REM stages in cycles of about 90 minutes. This calculator suggests bed or wake times around complete cycles.
Not medical advice.
About 90 minutes for many adults. Waking near cycle boundaries can feel easier than mid-cycle wake-ups.
Often 5–6 cycles (about 7.5–9 hours) plus fall-asleep time. Individuals vary.
Yes. Add your typical minutes so suggestions target actual sleep onset.
No. Educational only.