Shoe Size Conversion
EU 42, UK 8 or US 9 – you encounter different size specifications when buying shoes. A shoe size conversion helps compare EU, UK, and US shoe sizes. With our [shoe size converter], you can quickly transfer your known size to another sizing system. Additionally, a shoe size chart provides good guidance.
Why are there different shoe sizes?
Shoe sizes have evolved historically. Therefore, there is still no globally uniform sizing system. In Germany and large parts of Europe, EU shoe sizes are predominantly used. In Great Britain, UK sizes are common, and in the USA, US sizes.
The systems differ not only in numbering but also in their basis. A shoe size cannot therefore be reliably transferred from one system to another by simply adding or subtracting a fixed number.
For example, if you want to convert an EU shoe size to a UK shoe size, you should refer to a shoe size chart or the [shoe size converter].
EU Shoe Sizes and the Paris Point
The sizing system prevalent in Continental Europe is based on the so-called Paris point. One Paris point corresponds to two-thirds of a centimeter, or approximately 6.67 millimeters. A full EU size increment thus corresponds to one Paris point.
The system is also referred to as European, French, or EU shoe size. Specifications such as EU 39, EU 42, or EU 45 belong to this sizing system.
Unlike US sizes, there is no separate sizing scale for women and men within the European system. An EU 42 therefore fundamentally denotes the same size increment – regardless of whether it is a women's or men's shoe.
How to calculate your EU shoe size?
The measured foot length can be used as a guide. First, an allowance is factored in, and the resulting length measurement is then converted into the Paris point.
The calculation is:
(Foot length in cm + 1.5 cm) ÷ 0.667 = EU shoe size
However, this calculation only provides a guide. How a shoe actually fits also depends on its last shape, shoe width, upper material, and construction.
We explain how to properly measure your feet step-by-step under [Determine your own shoe size].
UK Shoe Sizes and the Barleycorn Principle
The British shoe sizing system traditionally uses the so-called Barleycorn as a unit of measurement. One Barleycorn corresponds to one-third of an inch, or approximately 8.46 millimeters.
One full UK size increment corresponds to one Barleycorn. Half UK sizes are also common for shoes, allowing for finer gradations in size selection.
Specifications such as UK 6, UK 6.5, or UK 7 belong to this system.
Sioux also uses UK sizes with half-size increments for its shoes. This allows for differentiated size selection and can be particularly helpful if you are between two classic EU sizes.
How to calculate your UK shoe size?
The UK size can also be approximately derived from the foot length.
The calculation for adult sizes is:
((Foot length in cm + 1.5 cm) ÷ 2.54 × 3) − 25 = UK shoe size
For practical size selection, a shoe size chart is usually simpler than doing your own calculation. However, the formula helps to understand how the British sizing system is structured.
How do US and UK shoe sizes differ?
The American shoe sizing system is related to the British system but uses a different numbering.
Additionally, there is an important difference: For US shoe sizes, there are different sizing scales for women and men. Therefore, a US size 9 for women's shoes does not correspond to the same size increment as a US 9 for men's shoes.
When converting US shoe sizes, you should always pay attention to whether the specification applies to women or men.
For adult sizes, the US size can be approximately calculated as follows:
Women:
(Foot length + 1.5 cm) ÷ 2.54 × 3 − 23
Men:
(Foot length + 1.5 cm) ÷ 2.54 × 3 − 24
Especially for US sizes, directly using a [shoe size chart] is usually clearer, as women's and men's sizes can be displayed separately there.
Directly compare EU, UK, and US sizes
If you already know a shoe size and simply want to know what size it corresponds to in another system, you don't need to perform the calculation yourself.
In our [shoe size chart], you can directly compare EU, UK, and US shoe sizes as well as the corresponding foot length. For US sizes, women's and men's sizes are listed separately.
It's even faster with our [shoe size converter]. There, you select the known size or the desired sizing system and directly receive the corresponding size orientation.
Why can the same shoe size fit differently?
Even a correctly converted shoe size does not automatically mean that every model in that size will fit the same.
How much space a shoe actually offers depends, among other things, on the following factors:
- the shape of the shoe last
- the shoe width
- the shape of the forefoot area
- the upper material
- the manufacturing method and construction of the shoe
For example, a narrowly cut model may feel different with the same size specification than a shoe with more room in the forefoot.
Therefore, the shoe size only describes part of the fit. The appropriate width is equally important. You can find out more about this under [Shoe widths at Sioux] and [Shoe size & fit].
What to consider for sneakers and sports shoes?
For sneakers and sports shoes, sizes can vary more depending on the brand and model. Internationally distributed models are also often marked in US sizes.
Therefore, do not assume that your usual size for a classic leather or street shoe will automatically fit a sneaker.
General recommendations such as "always buy sneakers one size larger" are not very helpful. Instead, refer to the sizing and fit information of the respective manufacturer.
Converting shoe sizes correctly
EU, UK, and US shoe sizes are based on different systems. A direct conversion therefore primarily provides a size orientation – the actual fit additionally depends on width, last shape, and model.
If you want to quickly compare a specific size, use our [shoe size chart]. The [shoe size converter] is also available for direct conversion.
This way, you can more reliably classify the different size specifications and then choose the size that, in combination with the appropriate shoe width and shape, best fits your foot.