US: 2T-4T to Europe Size 38-40
Cross-market children’s hats, beanies, caps, sun hats, and ear-flap hats apparel conversion mapping 2T-4T specifications into 38-40.

Analyzing Size Equivalence Across Markets
US: 2T-4T: Corresponds to a head circumference baseline of 50 (19.7 ) and age range 24–48 .
Europe Size 38-40: Corresponds to a head circumference baseline of 40 (15.7 ) and age range 0–3 .