United Kingdom Size 4-6 to US: 20-22

United Kingdom Size 4-6: Corresponds to a relaxed bust range of 78–82 $\text{cm}$ (30.7–32.3 $\text{in}$), elastic waist range of 60–64 $\text{cm}$ (23.6–25.2 $\text{in}$), and comfort drape classification Relaxed / Comfort Drape.

US: 20-22: Corresponds to a relaxed bust range of 113–117 $\text{cm}$ (44.5–46.1 $\text{in}$), elastic waist range of 95–100 $\text{cm}$ (37.4–39.4 $\text{in}$), and comfort drape classification Loose Lounge Fit.