sleep calculator

Wake up rested.

Sleep cycles are about 90 minutes long. Waking up between cycles feels much better than waking up in the middle of one.

wake-up time

to wake at 11:00 PM, fall asleep by:

6 cycles (9 h)OPTIMAL1:46 PM

5 cycles (7.5 h)OPTIMAL3:16 PM

4 cycles (6 h)4:46 PM

3 cycles (4.5 h)6:16 PM

How sleep cycles work. A full cycle is roughly 90 minutes and contains light sleep, deep sleep, and REM. Most adults need 5 to 6 cycles per night (7.5 to 9 hours). Allow about 14 minutes to actually fall asleep after lying down.