Dr. Julie M. Haas
Newborn 0-3 mos: 14-17 hr
Infant 4-11 mos: 12-16 hr
Toddler 1-2 yr: 11-14 hr
PS: 3-5 yr: 10-13 hr
6-12 yr: 9-12 hr
13-18 yr: 8-10 hr
American Academy of Sleep Medicine
J Clin Sleep Med 2016
If the baby isn't gaining weight he should be woken up to feed.
If weight is good, do not worry about time sleeping.
The most accurate answer comes with a few return questions of necessity to be most accurately responsive:
1) What has been your child's weight gain since birth at 3 kgs? A normal/average gain for this interval would be reassuring to you, and would put the issue of too much sleep to rest.
2) How many voids/day is your infant having? The average # would reflect adequate liquid intake.
3) Describe the character and # of stools per day. Again the range of normal would be reassuring as this reflects adequate breast milk or formula intake.
4) Do you breast or bottle feed? A well fed infant with either source tends to sleep comfortably for long intervals. Long restful sleep is the time of maximal growth, and reflects easy comfortable digestion of intake as well.
An infant that feeds well and lustily over a short interval, is sated, tends to fall asleep readily, and gives mom the gift vacuuming and dish washing time.
I look forward to responding again after reading your responses to the inquiry of 4 questions.