A shoe with a B width is narrower than the same shoe with a C width. Width sizing is alphabetical and can range from 2A to 7E.
Women's widths are marked by narrow (AA), average (B), wide (C/D) and extra-wide (E). Men's widths are marked by narrow (C), standard (D) or wide (E). The standard women's width is B, while men's standard width is D. Children's shoe width sizes range from N (narrow) to X-Wide (extra wide).
Variances in shoe widths may occur regardless of the sizing designation, because there is no standard width guideline by which every company must abide. A wide in one brand could be standard in another, so the best way to judge proper shoe width is with the help of a professional.