US: 9-11 to Europe Size 15-17
Cross-market children’s socks, tights, hosiery, leg warmers, and dance tights sizing conversion mapping 9-11 specifications into 15-17.

Analyzing Size Equivalence Across Markets
US: 9-11: Corresponds to a foot length of 23 (9.1 ), matching US shoe size 4-7, and age range 120–168 months.
Europe Size 15-17: Corresponds to a foot length of 9.5 (3.7 ), matching US shoe size 1-2, and age range 0–6 months.