Sleep cycle calculator
◆ Go to bed at
10:46PM
best window 10:30 – 11:00 PM · to wake at 6:30 AM
Wake up at
Sleep for
No 7h or 8h: sleep runs in ~90-min cycles, and those wake you mid-cycle. 7½h (5 cycles) is the cycle-aligned “8 hours.”
remembered for next time
tonight's full plan →sources: AASM · NSF
Or pick your question · 18 calculators
Timing · 05
Cutoffs · 02
method last reviewed May 2026