We use two size scales: AA, A, B, D, E, 3E, 5E and N, M, W. The D and M are equivalent for medium or (standard). The B and N are equivalent for Narrow. The 3E and W are equivalent for Wide. Measure your feet from the heel to the tip of your longest toe. Using the conversion tables, find the closest measurement in inches that is equal to or greater than the length of your foot. Then, measure your foot at the widest part and use the chart to find the measurement closest in inches to the width of your foot.
To ensure an accurate reading when measuring, flatten your foot shifting your weight forward.
If you measure between two sizes always go to the larger size.
Measure later in the day. Your feet expand throughout the day.