US: 3XL to Europe Size 58
Cross-market men’s hat and headwear conversion mapping 3XL specifications into 58.

Analyzing Hat Size Equivalence Across Markets
US: 3XL: Features a head circumference of 64.5 (25.4 ), measured above the ears where the hat sits comfortably.
Europe Size 58: Features a head circumference of 58.5 (23 ), measured above the ears where the hat sits comfortably.