When trying to decide between two sizes, choose the larger size for a better fit.

SizeSize/Age RangeChestWaistHeightWeight
0-6 MonthsNewborn-6 months8.75"8.75"22"-24"10-16
6-12 Months6 Months-12 Months9.75"9.75"25"-28"17-20
12-18 Months12 Months-18 Months10.75"10.75"29"-31"21-24