US: 38-40 to United Kingdom Size 46-48

US: 38-40: Corresponds to a relaxed chest range of 98–102 $\text{cm}$ (38.6–40.2 $\text{in}$), elastic waist range of 84–90 $\text{cm}$ (33.1–35.4 $\text{in}$), and fit classification Relaxed / Comfort Fit.

United Kingdom Size 46-48: Corresponds to a relaxed chest range of 114–118 $\text{cm}$ (44.9–46.5 $\text{in}$), elastic waist range of 100–106 $\text{cm}$ (39.4–41.7 $\text{in}$), and fit classification Loose Lounge Fit.