Infants wear different shoe sizes as they grow, and no two infants are exactly the same as to at what point their feet matches any particular size; however, generally speaking, newborns wear U.S. size 0 and Euro size 16 to about 6 weeks and US1/Euro17 until 3 months.
U.S. size 1 infant shoes are 3.33 inches in length. U.S. size 2 infant shoes, Euro size 18 fit 3- to 6-month-olds and are 3.67 inches long. Infant sizes U.S. 3 and 3.5 and Euro 18 fit 6- to 9-month-olds, and U.S. 4 and 4.5 and Euro 19 fit 9- to 12-month-olds.
