Shoe size
A shoe size is an indication of the fitting size of a shoe for a person.
There are a number of different shoe-size systems used worldwide. While all shoe sizes use a number to indicate the length of the shoe, they differ in exactly what they measure, what unit of measurement they use, and where the size 0 (or 1) is positioned. Some systems also indicate the shoe width, sometimes also as a number, but in many cases by one or more letters. Some regions use different shoe-size systems for different types of shoes (e.g. men’s, women’s, children’s, sport, and safety shoes). This article sets out several complexities in the definition of shoe sizes. In practice, shoes should be tried on for size and fit before they are purchased.
The length of a person’s foot is commonly defined as (a) the distance between two parallel lines that are perpendicular to the foot and (b) in contact with the most prominent toe and the most prominent part of the heel. Foot length is measured with the subject standing barefoot and the weight of the body equally distributed between both feet.
The sizes of the left and right feet are often slightly different. In this case, both feet are measured, and purchasers of mass-produced shoes are advised to purchase a shoe size based on the larger foot, as most retailers do not sell pairs of shoes in non-matching sizes.
Each size of shoe is considered suitable for a small interval of foot lengths, typically limited by half-point of the shoe size system.
A shoe-size system can refer to three characteristic lengths:
The median length of feet for which a shoe is suitable. For customers, this measure has the advantage of being directly related to their body measures. It applies equally to any type, form, or material of shoe. However, this measure is less popular with manufacturers,[citation needed] because it requires them to test carefully for each new shoe model, for which range of foot sizes it is recommendable. It puts on the manufacturer the burden of ensuring that the shoe will fit a foot of a given length.
The length of the inner cavity of the shoe.
This measure has the advantage that it can be measured easily on the finished product. However, it will vary with manufacturing tolerances and only gives the customer very crude information about the range of foot sizes for which the shoe is suitable.
The length of the “last”, the foot-shaped template over which the shoe is manufactured. This measure is the easiest one for the manufacturer to use, because it identifies only the tool used to produce the shoe. It makes no promise about manufacturing tolerances or for what size of foot the shoe is actually suitable. It leaves all responsibility and risk of choosing the correct size with the customer.
Further, the last can be measured in several different ways resulting in different measurements.
All these measures differ substantially from one another for the same shoe. For example, the inner cavity of a shoe must typically be 15 mm longer than the foot, and the shoe last would be 2 size points larger than the foot, but this varies between different types of shoes and the shoe size system used. The typical range lies between 1⁄2 to 2⁄3 inch (12.7 to 16.9 mm) for the UK/US size system and 4⁄3 to 5⁄3 cm (13.3 to 16.7 mm) for the European size system, but may extend to 1⁄4 to 3⁄4 inch (6.4 to 19.1 mm) and 2⁄3 to 6⁄3 cm (6.7 to 20.0 mm).
