Shoe size is crucial when it comes to buying shoes that fit properly. As we all know, shoe size represents the length of the shoe. To regulate shoe sizing across different regions, there are two important standards: ISO 19407:2015 Footwear – Sizing – Conversion of sizing systems and GB/T 36935-2018 Conversion of sizing systems
These two standards introduce the three main shoe size systems in the world: Mondopoint, EUR and UK. Most international shoe sizes are based on these three systems.
1. Mondopoint
The shoe size is based on foot length and is represented by foot length data. For example, if the foot length is 220mm, the shoe size is denoted by 220.
Here are two more things to add:
1) Shoe size can also include foot width, e.g. 264/94
2) Foot length can also be expressed in cm. For example, Japanese shoe size is sometimes expressed in cm instead of mm.
China’s shoe size is also implemented in accordance with Mondopoint. But our consumers in China see shoe size on many shoes with two-digit numbers, such as 36 and 42. What does that mean? It turns out that this is the old shoe size representation. This method is also based on the length of the foot, according to the following formula conversion.
L÷5-10
（L stands for foot length）
For example, if the foot length is 220mm, the old shoe size is 220÷5-10=34.
In this way, Mondopoint is far more intuitive.
2. EUR
The European shoe size was formerly known as the Paris shoe size, French shoe size, or Continental shoe size. The length grading interval (difference between adjacent whole shoe sizes) is 6.67mm. It is based on the length of the shoe or last.
Its algorithm also has a formula:
(L stands for foot length)
For example, if the foot length is 240mm, the suitable shoe size is [240+(2 × 6.67)]÷6.67=38.
3. UK
British shoe sizes are also based on shoe length or last length. Its size difference (the length difference between adjacent shoe sizes) is 8.47mm. There are 13 shoe sizes ranging from 101.6mm (4 inch) to 211.7mm (8 1/3 inch), belonging to children’s shoe sizes. For adult shoes, the starting point is 211.7mm and start again at 1. The formula of its adult shoe size is:
(L stands for foot length)
For example, if the foot length is 255mm, the suitable shoe size is [255+(2 x 8.47)]÷8.47-25=7.
The US shoe size system is the same as the UK shoe size system, but for children’s shoes in the US, 0.5 should be added on the basis of the UK. For men’s shoes, 1 should be added, and for women’s shoes, 2 should be added.
For instance, if the adult foot length is 240mm, shoe sizes for each system are as follows:
