Hi, welcome to the ehealth forum and I am glad to help you.
You want to know about the average sleeping hours for a 4 year old baby.
Children at this age typically go to bed between 7 and 9 p.m. and wake up around 6 and 8 a.m., just as they did when they were younger. At 3, most children are still napping while at 5, most are not. Naps gradually become shorter as well. New sleep problems do not usually develop after 3 years of age.
Hope this helps. Take care.
Note: This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.