US: 12-4E to United Kingdom Size 6-B

US: 12-4E: Corresponds to a foot length of 30.2 $\text{cm}$ (11.89 $\text{in}$), ball width of 12 $\text{cm}$ (4.72 $\text{in}$), acceptable ball width range between 11.7–12.4 $\text{cm}$ (4.61–4.88 $\text{in}$), and fit classification Extra-Wide (12-4E / EEEE).

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).