United Kingdom Size 4–6 to US: XL (16–18)

United Kingdom Size 4–6: Waist contouring range of 58.4–63.5 $\text{cm}$ (23–25 $\text{in}$), full hip range of 83.8–88.9 $\text{cm}$ (33–35 $\text{in}$), style variants Thongs, Bikinis & Cheeky Cuts, and fit classification Petite Contour Fit.

US: XL (16–18): Waist contouring range of 83.8–88.9 $\text{cm}$ (33–35 $\text{in}$), full hip range of 109.2–114.3 $\text{cm}$ (43–45 $\text{in}$), style variants Full Briefs, High-Waist & Boy Shorts, and fit classification Generous Full Fit.