About this tool
Enter your foot width, US shoe size and gender and this calculator returns your shoe width letter — such as B, D, 2E or 4E — along with the narrow-to-wide category and the nominal medium width for your size. It works from built-in width charts in your browser, with no uploads. Foot width is the widest part of the foot across the ball, measured in inches or centimetres.
Each US shoe size has a nominal 'medium' ball width: D for men and B for women. The tool looks up that medium for your size, then compares your measured width to it. Every width grade is about 3/16 of an inch (0.1875") apart, so it divides the difference by that step and moves along the width scale — AAA, AA, A, B, C, D, E, 2E, 3E, 4E for men (medium D), and up to 2E for women (medium B). A width at the medium is standard; each step wider adds an E-grade, each step narrower drops toward the A-grades.
To measure, stand with weight on the foot and measure straight across the widest part of the ball. The category groups the result as narrow, medium, wide or extra wide. Fit standards differ between shoemakers and lasts, so these widths are approximate and vary by brand — try the shoe on where you can.