US: 9-B to United Kingdom Size 8-AA

US: 9-B: Corresponds to a foot length of 26.2 $\text{cm}$ (10.31 $\text{in}$), ball width of 9.9 $\text{cm}$ (3.9 $\text{in}$), acceptable ball width range between 9.6–10.1 $\text{cm}$ (3.78–3.98 $\text{in}$), and fit classification Narrow (9-B / AA).

United Kingdom Size 8-AA: Corresponds to a foot length of 25.2 $\text{cm}$ (9.92 $\text{in}$), ball width of 9.3 $\text{cm}$ (3.66 $\text{in}$), acceptable ball width range between 9.1–9.5 $\text{cm}$ (3.58–3.74 $\text{in}$), and fit classification Extra Narrow (9-3A / AAAA).