US: 54-56 to United Kingdom Size 38-40

US: 54-56: Corresponds to a relaxed chest range of 130–134 $\text{cm}$ (51.2–52.8 $\text{in}$), elastic waist range of 116–122 $\text{cm}$ (45.7–48 $\text{in}$), and fit classification Loose Lounge Fit.

United Kingdom Size 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.