United Kingdom Size 6-D to US: 5-2A

United Kingdom Size 6-D: Corresponds to a forefoot ball width of 9.5 $\text{cm}$ (3.74 $\text{in}$), ball width range of 9.3–9.7 $\text{cm}$ (3.66–3.82 $\text{in}$), reference foot length of 23.5 $\text{cm}$ (9.25 $\text{in}$), and fit classification Wide (8-D).

US: 5-2A: Corresponds to a forefoot ball width of 7.9 $\text{cm}$ (3.1 $\text{in}$), ball width range of 7.7–8.1 $\text{cm}$ (3.05–3.2 $\text{in}$), reference foot length of 21.9 $\text{cm}$ (8.6 $\text{in}$), and fit classification Narrow (5-2A / A).