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

SizeChestWaistHipsHeightWeight
0-9 months18''18''18''26''18-19 lbs.
12-18 months20''20''20''31.5''23-24 lbs.
1T-2T21''20''21''33.5''25-26 lbs.
3T-4T23''21''23''41.5''34-36 lbs.