Host: How much sleep does an average adult and child need? Jeannette Bessinger: The average person typically needs between seven and nine hours of sleep per night. They have done some very interesting studies where they remove all external cues. What they discover is most people tend without external stimulation to sleep about eight-and-half hours per night. Most school aged children need between eight-and-a-half and ten hours per night depending on their age, even your high Schooler.