US: 8-10 to United Kingdom Size 20-22
Cross-market women’s sleepwear conversion mapping 8-10 specifications into 20-22 for nightgowns, pajama sets, and sleep shirts.

Analyzing Women’s Sleepwear Equivalence Across Markets
US: 8-10: Corresponds to a relaxed bust range of 90–94 (35.4–37 ), elastic waist range of 72–76 (28.3–29.9 ), and comfort drape classification Relaxed / Comfort Drape.
United Kingdom Size 20-22: Corresponds to a relaxed bust range of 105–109 (41.3–42.9 ), elastic waist range of 87–92 (34.3–36.2 ), and comfort drape classification Loose Lounge Fit.