US: 9-11 to Europe Size 27-30
Cross-market children’s socks, tights, hosiery, leg warmers, and dance tights sizing conversion mapping 9-11 specifications into 27-30.

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 27-30: Corresponds to a foot length of 17.5 (6.9 ), matching US shoe size 10-12, and age range 48–84 months.