US: 4-6 to United Kingdom Size 4-6
Cross-market women’s sleepwear conversion mapping 4-6 specifications into 4-6 for nightgowns, pajama sets, and sleep shirts.

Analyzing Women’s Sleepwear Equivalence Across Markets
US: 4-6: Corresponds to a relaxed bust range of 84–88 (33.1–34.6 ), elastic waist range of 66–70 (26–27.6 ), and comfort drape classification Relaxed / Comfort Drape.
United Kingdom Size 4-6: Corresponds to a relaxed bust range of 78–82 (30.7–32.3 ), elastic waist range of 60–64 (23.6–25.2 ), and comfort drape classification Relaxed / Comfort Drape.