Measure Your Feet Day

What the day is

Measure Your Feet Day is observed on January 23. No origin is documented, and the instruction is more sensible than it first appears.

Origin and background

Most adults settle on a shoe size in their twenties and never measure again, on the assumption that feet are finished growing. They are not finished changing. The ligaments supporting the arch gradually lengthen with age and load, so feet tend to get longer and wider over the decades. Pregnancy produces the same effect more quickly, often permanently. Significant weight change alters it. So does a foot that has been injured or operated on.

Sizing itself is also less reliable than it looks. There is no single international standard, and the American, British, European and Japanese systems measure different things in different units. Worse, manufacturers work to their own lasts, so a nominal size varies between brands and between models from one brand. The number on the box is an approximation of a shape, not a measurement of your foot.

The practical consequences are not trivial. Surveys of older adults repeatedly find a large proportion wearing shoes narrower or shorter than their measured feet, and poorly fitted footwear is associated with foot pain, deformity and falls. For anyone with diabetes it matters more again, because reduced sensation means a rubbing shoe may not be felt until it has caused a wound.

Two details make measuring worthwhile. Feet swell over the day, so an afternoon measurement reflects reality better than a morning one. And most people have one foot noticeably larger than the other, which should determine the size rather than the average.

How to take part

• Measure both feet, standing, with your weight on them.
• Measure late in the day when they are at their largest.
• Fit to the larger foot, always.
• Check width as well as length, which is the dimension shops most often ignore.
• Measure children every couple of months, since their feet change fast and they will not complain.