Baby Size Chart

Size	Child's Weight	Child's Length
Newborn	8-12 lbs	up to 23 in
0-3 Months	12-16 lbs	up to 29 in
3-6 Months	16-19 lbs	26-30 in
6-12 Months	19-24 lbs	30-33 in
12-18 Months	24-29 lbs	33-35 in
18-24 Months	29-34 lbs	35-41 in

 

These pajamas tend to run larger due to the amount of stretch. The pictures below show an example of the same pajamas (6-12m) on a 6 month old, 9 month old, and 15 month old.