We recommend sticking true to size and age for your child. Zippy is designed to grow with them, lasting up to 3x longer with convertible hand and foot covers.

Size	Height	Weight
Newborn	18-22"	8-11lbs
0-3m	22-25"	8-14lbs
3-6m	24-27"	14-17lbs
6-9m	26-28"	17-20lbs
9-12m	27-30"	19-22lbs
12-18m	29-32"	22-26lbs