It is important to understand that the measurement of a shoe’s width is not necessarily the measurement we take when we measure the foot. What do we mean by that? The measurement of a “last” width, or the width marking the shoe, is the girth measurement at the ball of the shoe. However, when we take a width measurement with a foot-measuring device, we are measuring the linear width of the foot at the ball.

As previously mentioned, the width measurement of the “last,” and thus the shoe, is a girth measurement, not a linear measurement. Thus when you are measuring the foot you are only getting a one- dimensional measurement. That is why foot evaluation is as important as the measurement. If your foot is very full and fleshy or has a very high instep, you must take this into consideration when selecting the shoe width. The width you measure with the measuring device, or the linear width of the foot, may not reflect the amount of volume of the foot or the width/ girth needed to properly fit the foot.

Also, when a shoe width changes from a D to E, the change may not translate to the shoe being wider across the bottom of the shoe or foot. In fact, the linear measurement may remain the same, but the shoe is wider because it is fuller or has more material across the upper.

The difference in each width is ? inch. For each change in width  (B to C to D, Etc.), there is ? inch change in girth at the ball of the foot. As a shoe goes up in length, a ? inch increase in girth occurs automatically with each increase of a full size. Remember, each time a “last”/ shoe increases in length; there is a proportional increase in size or measurement.  Even though both are marked a B width, it stands to reason that you pick up more ball width with increased size, even though the width size remains the same.