PLEASE MEASURE BABY'S FEET FOR THE PERFECT FIT! To determine the appropriate size for your baby is, to measure lengths from the longest toe to the end of the heel. Shoe Sizes: Newborn (3.5 inches) Shoes Size 0-3 0-6 months (4 inches) Shoe Size 3 6-12 months (4.5 inches) Shoe Size 4 12-18 months (5 inches) Shoe Size 5-6 18-24 months (5.5inches) Shoe Size 7-8 Washable: Please wash them in cold water, air dry. Adjustable ankle straps: Fold back the upper front part. There is a double knot on the elastic band. You can make it tighter or looser. Just carefully untie the strap, holding onto both ends. Adjust it as needed and tie an other knot on it. Once adjusted to baby's feet, take one side of the strap and pull it, so the knot slides in the housing. This way you can adjust it exactly to Baby's feet.