US: 8-D to United Kingdom Size 6-B

US: 8-D: Corresponds to a foot length of 25.2 $\text{cm}$ (9.92 $\text{in}$), ball width of 10 $\text{cm}$ (3.94 $\text{in}$), acceptable ball width range between 9.7–10.3 $\text{cm}$ (3.82–4.06 $\text{in}$), and fit classification Standard Width (8-D / M).

United Kingdom Size 6-B: Corresponds to a foot length of 24.5 $\text{cm}$ (9.65 $\text{in}$), ball width of 9.6 $\text{cm}$ (3.8 $\text{in}$), acceptable ball width range between 9.3–9.8 $\text{cm}$ (3.65–3.85 $\text{in}$), and fit classification Narrow (7-B / AA).