US: 10–12.5 to Europe Size 38–40
Cross-market women’s sock and hosiery conversion mapping 10–12.5 specifications into 38–40.

Analyzing Women’s Sock Size Equivalence Across Markets
US: 10–12.5: Corresponds to a foot length range of 25.5–27.5 (10–10.8 ), US shoe size bracket of 10–12.5, and fit classification Comfort Stretch / Ankle Grip.
Europe Size 38–40: Corresponds to a foot length range of 23.5–25 (9.3–9.8 ), US shoe size bracket of 7–9.5, and fit classification Comfort Stretch / Ankle Grip.