US: 12-14 to United Kingdom Size 24-26
Cross-market women’s sleepwear conversion mapping 12-14 specifications into 24-26 for nightgowns, pajama sets, and sleep shirts.

Analyzing Women’s Sleepwear Equivalence Across Markets
US: 12-14: Corresponds to a relaxed bust range of 97–101 (38.2–39.8 ), elastic waist range of 79–84 (31.1–33.1 ), and comfort drape classification Relaxed / Comfort Drape.
United Kingdom Size 24-26: Corresponds to a relaxed bust range of 113–117 (44.5–46.1 ), elastic waist range of 95–100 (37.4–39.4 ), and comfort drape classification Loose Lounge Fit.