Sleep Calculator
Find optimal bedtime and wake-up times based on 90-minute sleep cycles.
Go to bed at one of these times to wake up feeling refreshed:
Wake up at one of these times to complete a full sleep cycle:
If you fall asleep now (+ ~14 min to fall asleep), wake up at:
Each sleep cycle ≈ 90 minutes. Waking at the end of a cycle reduces grogginess. Adults need 5–6 cycles (7.5–9 hours). Add 14 minutes to fall asleep.