US: L/XL to United Kingdom Size 6 1/2
Cross-market women’s hat conversion mapping L/XL specifications into 6 1/2.

Analyzing Hat Size Equivalence Across Markets
US: L/XL: Features a head circumference of 59.5 (23.4 ) measured just above the brow and ears.
United Kingdom Size 6 1/2: Features a head circumference of 53 (20.9 ) measured just above the brow and ears.