United Kingdom Size 6-D to US: 9-2A

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: 9-2A: Corresponds to a forefoot ball width of 8.9 $\text{cm}$ (3.5 $\text{in}$), ball width range of 8.7–9.1 $\text{cm}$ (3.42–3.58 $\text{in}$), reference foot length of 24 $\text{cm}$ (9.45 $\text{in}$), and fit classification Narrow (9-2A / A).