US: XL to United Kingdom Size 6

US: XL: Corresponds to a waist/hip size of 90 $\text{cm}$ (36 $\text{in}$), waist range of 81–91 $\text{cm}$ (31.9–35.8 $\text{in}$), total strap length of 100 $\text{cm}$ (39.4 $\text{in}$), and fit classification Relaxed Waist / Hip.

United Kingdom Size 6: Corresponds to a waist/hip size of 70 $\text{cm}$ (28 $\text{in}$), waist range of 60–70 $\text{cm}$ (23.6–27.6 $\text{in}$), total strap length of 80 $\text{cm}$ (31.5 $\text{in}$), and fit classification Waist / Snug Cinch.