A shoe size is an alphanumerical indication of the fitting size of a shoe for a person. Often it just consists of a number indicating the length because many shoemakers only provide a standard width for economic reasons.
There are several different shoesize systems that are used worldwide. These systems differ in what they measure, what unit of measurement they use, and where the size 0 (or 1) is positioned. Only a few systems also take the width of the feet into account. Some regions use different shoesize systems for different types of shoes (e.g., men's, women's, children's, sport, or safety shoes).
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The length of a foot is commonly defined as the distance between two parallel lines that are perpendicular to the foot and 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 on both feet.
The size of the left and right foot is often slightly different. In this case, both feet are measured, and the shoe size is based upon the larger foot.
Each size of shoe is suitable for a small interval of foot lengths. The inner cavity of a shoe must typically be 15–20 mm (0.6–0.8 in) longer than the foot, but this relation varies between different types of shoes.
There are three characteristic lengths that a shoesize system can refer to:
All these measures differ substantially from one another for the same shoe.
Sizing systems also differ in what units of measurement they use. This also results in different increments between shoe sizes because usually, only "full" or "half" sizes are made.
The following length units are commonly used today to define shoesize systems:
Due to the different units of measurements, converting between different sizing systems results in roundoff errors as well as unusual sizes such as "10⅔".
The sizing systems also place size 0 (or 1) at different locations:
Some systems also include the width of a foot. There are different methods indicating the width:
The exact foot width for which these sizes are suitable can vary significantly between manufacturers. The AE width indicators used by some US and UK shoe manufacturers are typically based on the width of the foot, and common step sizes are 1/16 of an inch.
The International Standard is ISO 9407:1991, Shoe sizes—Mondopoint system of sizing and marking,^{[2]} that recommend a shoesize system known as Mondopoint.
It is based on the mean foot length and width for which the shoe is suitable, measured in millimetres. A shoe size of 280/110 indicates a mean foot length of 280 millimetres (11 in) and width of 110 millimetres (4.3 in).
Because Mondopoint also takes the foot width into account, it allows for better fitting than most other systems. It is, therefore, used by NATO and other military services.
European standard EN 13402, used also for clothes, recommends, instead, that shoes be labelled with the interval of foot lengths for which they are suitable, measured in centimetres.
Shoe size in the United Kingdom (British size) is based on the length of the last, measured in barleycorn (approx 1/3 inch) starting from the smallest practical size, which is size zero. It is not formally standardised.
A child's size zero is equivalent to a hand (4 in, 12 barleycorns or 10.16 cm), and the sizes go up to size 13½ (8½ in or 21.59 cm). Thus, the calculation for a child shoe size in the UK is:
An adult size one is then the next size up (8⅔ in or 22.01 cm) and each size up continues the progression in barleycorns.^{[3]} The calculation for an adult shoe size in the UK is thus:
In North America, there are different systems that are used concurrently. The size indications are usually similar but not exactly equivalent, especially with athletic shoes at extreme sizes.
The traditional system is similar to English sizes but start counting at one rather than zero, so equivalent sizes are one greater. (This is similar to the way that floors in buildings are numbered from one rather from zero (ground) in these regions).
So the calculation for a male shoe size in the USA or Canada is:
Women's sizes are almost always determined with the "common" scale, in which women's sizes are equal to men's sizes plus 1.5 (for example, a men's 10.5 is a women's 12). In other words:
In the less popular scale, known as the "standard" or "FIA" (Footwear Industries of America) scale, women's sizes are men's sizes plus 1 (so a men's 10.5 is a women's 11.5).
Children's sizes are equal to men's sizes plus 12.33. Thus, girls' and boys' sizes do not differ, even though men's and women's do.
Children's shoe stores in the United States use a sizing scheme which ends at 13, after which it starts at 1 again as adult sizes.
Shoe Size  Inches  Centimeters 

5  4 13/16  12 
6  5 1/8  13 
7  5 1/2  14 
8  5 13/16  15 
9  6 1/8  15,5 
10  6 1/2  16,5 
11  6 13/16  17,5 
12  7 1/8  18 
13  7 1/2  19,1 
1  7 13/16  20 
2  8 1/8  20,5 
3  8 1/2  21,5 
4  8 13/16  22,4 
5  9 1/8  23 
6  9 1/2  24 
7  9 13/16  25 
A slightly different sizing method is based on a measurement device designed by shoe seller Charles Brannock.Many are now found in shoe stores. Men's size 1 is equivalent to a foot's length of 7 ⅔ in;^{[4]} women's sizes are one size up.
The method also measures the length of the distance of the heel and the widest point of the foot. For that purpose, the device has another, shorter scale at the side of the foot. If this scale indicates a larger size, it is taken in place of the foot's length.^{[5]}
For children's sizes, additional wiggle room is added to allow for growth.^{[5]}
The device also measures the width of the foot and assigns it designations of AAA, AA, A, B, C, D, E, EE, or EEE. The widths are 1/16 in apart and differ by shoe length.^{[4]}
Some makers of athletic shoes, such as Nike, Reebok, or Fila, use an increment of 5 mm instead of half a barleycorn (4.23 mm)^{[6]} As with other systems, women's sizes are one size up.
There are different sizes for children's and youths' shoes, for example, Nike uses the following:
It is obvious that due to the different increments, the sizes can be similar to “normal” US sizes only for medium shoe sizes. For shoes that are larger or smaller, the sizes deviate substantially.
^{[citation needed]}
The Continental European system is used in France, Germany,^{[7]} Italy, Spain,^{[8]} and most other continental European countries.
In this system, the shoe size is the length of the last, expressed in Paris points, for both genders and for adults and children alike. Because a Paris point is ⅔ of a centimetre and the last must be same length of the foot ("perfect fitting"), the formula is as follows:
The Asian system is based on metric measurements and standardised as JIS S 5037:1998, CNS 4800, S 1093, or KS M 6681. Foot length and girth are taken into account.^{[9]}
The foot length is indicated in centimetres; an increment of 5 mm is used. This system was also used in the GDR.
The length is followed by designators for girth (A, B, C, D, E, EE, EEE, EEEE, F, G), which is taken from a table indexed to girth and length. There are different tables for men's, women's, and children's (less than 12 years of age) shoes. The tables also include the width as supplemental indications. Not all designators are used for all genders and in all countries. For example, the largest girth for women in China is EEEE, whereas in Japan, it is F.
In Japan, one maker also adds an indication for the foot width: N (narrow), M (medium), and W (wide).^{[10]}
Please, note that the following tables indicate theoretical sizes calculated from the standards and information given above. Differences between these tables and makers' tables or other tables found on the Web are usually due to the following factors:
Further, some tables available on the Web simply contain errors. For example, the wiggle room or different zero point is not taken into account, or tables based on different U.S. systems (traditional and athletic) are simply combined although they are incompatible.
Example: A child's foot that is 185 millimetres (7.3 in) long requires a shoe that is about 15 millimetres (0.59 in) longer. The inner length of 200 millimetres (7.9 in) is EU shoe size 30 or UK size 11.5.
