United Kingdom Size Slim Fit to US: Classic Regular / 53mm

United Kingdom Size Slim Fit: Corresponds to a nominal width of 47 $\text{mm}$ (1.85 $\text{in}$), length of 170 $\text{mm}$ (6.69 $\text{in}$), average structural girth of 94 $\text{mm}$ (3.7 $\text{in}$), and fit category Snug / Slim.

US: Classic Regular / 53mm: Corresponds to a nominal width of 53 $\text{mm}$ (2.09 $\text{in}$), length of 190 $\text{mm}$ (7.48 $\text{in}$), average structural girth of 106 $\text{mm}$ (4.17 $\text{in}$), and fit category Standard / Original.