Itty Bitty Baby Size Charts

Clothing

Size Approximate Age  Weight
 Preterm 1 n/a up to 1 lb / up to 454 grams
 Preterm 2 24-30 weeks gestation 1-3 lbs / 454-1360 grams
 Preterm 3 30-36 weeks gestation 3-5 lbs / 1.4-2.3 kg
 1 month up to 1 month 5-8 lbs / 2.3-3.6 kg
 1-3 months 1-3 months 8-12 lbs / 3.6-5.4 kg
 3-6 months 3-6 months 12-17 lbs / 5.4-7.7 kg
 6-9 months 6-9 months 17-22 lbs / 7.7-10 kg
 9-12 months9-12 months  22-27 lbs / 10-12.2 kg

Cotton Print Sleepers

SizeLength (shoulder to heel)
 Preterm 3 15 inches
 1 month 16.5 inches
 1-3 months 19 inches
 3-6 months 20.5 inches
 6-9 months 25.5 inches
 9-12 months 27.5 inches

Cotton Print Nightie Bag

SizeLength
 Preterm 3 16 inches
 1 month 18 inches
 1-3 months 20 inches

Hat/Beanies

SizeApproximate AgeHead CircumferenceWeight
 Mini Micro-Preemie 22-27 weeks 8-10 inches1-3 lbs
 Micro-Preemie 27-33 weeks 10-12 inches3-5 lbs 
 Preemie 33-38 weeks 12-14 inches 5-7 lbs
 0-6 months 0-6 months 15-17 inches 7-15 lbs
 6-12 months 6-12 months 17-19 inches 15-26 lbs
 12-24 months 12-24 months 19-21 inches 26-36 lbs

Footwear

SizeApproximate AgeFoot Length
 Preterm 3 30-36 weeks gestation up to 2.5 inches
 1 month up to 1 month up to 3.5 inches
 1-3 months 1-3 months up to 4.5 inches
 0-6 months 0-6 months up to 4 inches
 6-12 months 6-12 months up to 5 inches

Mittens

 Size Approximate Weight Hand size (length by width)
 Mini Micro-Preemie up to 3 lbs 2 inches by 2.25 inches
 Preemie 3-7 lbs 2.25 inches by 2.5 inches
 Newborn 7+ lbs 3 inches by 3 inches