US: 4-7Y to Europe Size 49-51
Cross-market children’s hats, beanies, caps, sun hats, and ear-flap hats apparel conversion mapping 4-7Y specifications into 49-51.

Analyzing Size Equivalence Across Markets
US: 4-7Y: Corresponds to a head circumference baseline of 53 (20.9 ) and age range 48–84 .
Europe Size 49-51: Corresponds to a head circumference baseline of 50 (19.7 ) and age range 24–48 .