Sleep Calculator
Optimal wake times based on 90-minute sleep cycles.
Sleep cycles last about 90 minutes. Waking between cycles often feels easier than waking mid-cycle. Enter when you go to bed (or when you must wake up) to see suggested alarm times.
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Frequently Asked Questions
Sleep cycles are ~90-minute periods. Waking between cycles feels better than mid-cycle. We calculate wake times so you rise at cycle boundaries.
Most people fall asleep in 10–20 minutes. Our calculator adds 15 minutes by default. Adjust if you fall asleep faster or slower.
Most adults need 5–6 cycles (7.5–9 hours). The calculator shows options for 4–6 cycles.
Sleep debt, stress, and screen time before bed matter. Use these times as a guide, not a guarantee.