While getting seven to nine hours of sleep is a good general guideline for most adults, the number of sleep cycles you experience and the time spent in each.
According to Johns Hopkins pediatrician Michael Crocetti, M.D., M.P.H., teens need 9 to 9½ hours of sleep per night—that's an hour or so more than they needed.
By about 2 years Your child needs about 11 to 12 hours of sleep a night. They need 1 nap during the day for up to 2 hours. Avoid naps after 3.30pm so they will.
The optimal amount of sleep for teens between the ages of 13 to 18 is around 8 to 10 hours a night. This recommendation differs for both preteens and young.