Size 0 (Preemie) up to approx 14 lbsSize 1 (0-6 mo) up to approximately 18 lbsSize 2 (6-12 mo) up to approximately 22 lbsSize 3 (12-18 mo) up to approximately 26 lbsSize 4 (18-24 mo) up to approximately 29 lbsSize 5 (3 Toddler) up to approximately 34 lbs