US: 11–13 to United Kingdom Size 13–14.5
Cross-market men’s sock conversion mapping 11–13 specifications into 13–14.5.

Analyzing Sock Size Equivalence Across Markets
US: 11–13: Corresponds to a US shoe size range of 11–13, foot length of 28.5–30 (11.2–11.8 ), and fit classification Relaxed / Comfort Stretch.
United Kingdom Size 13–14.5: Corresponds to a US shoe size range of 13.5–15, foot length of 30.5–32 (12–12.6 ), and fit classification Extended Volume / High Stretch.