United Kingdom Size Large to US: Standard / 52mm

United Kingdom Size Large: Corresponds to a nominal width of 57 $\text{mm}$ (2.24 $\text{in}$), length of 200 $\text{mm}$ (7.87 $\text{in}$), average structural girth of 114 $\text{mm}$ (4.49 $\text{in}$), and fit category Large / Roomy.

US: Standard / 52mm: Corresponds to a nominal width of 52 $\text{mm}$ (2.05 $\text{in}$), length of 185 $\text{mm}$ (7.28 $\text{in}$), average structural girth of 104 $\text{mm}$ (4.09 $\text{in}$), and fit category Standard / Regular.