US: XS (26–28) to United Kingdom Size 38–40

US: XS (26–28): Corresponds to a waist stretch range of 66–71 $\text{cm}$ (26–28 $\text{in}$), hip circumference of 84 $\text{cm}$ (33 $\text{in}$), thigh clearance of 48 $\text{cm}$ (18.9 $\text{in}$), and fit style Briefs, Trunks & Boxer Briefs.

United Kingdom Size 38–40: Corresponds to a waist stretch range of 96.5–101.6 $\text{cm}$ (38–40 $\text{in}$), hip circumference of 111.8 $\text{cm}$ (44 $\text{in}$), thigh clearance of 63 $\text{cm}$ (24.8 $\text{in}$), and fit style Relaxed Boxers & Extended Boxer Briefs.