Shoe size conversion
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Shoe size conversion made easy

Converting shoe sizes is a breeze thanks to our online calculator. You can calculate the right shoe size with just a click here. Whether it is EU (Paris point), UK, US or by entering the length of your feet in cm, our online shoe size calculator can convert any shoe size into any desired major international shoe size measurement.

Please enter the size to be converted into one of the fields and then click the “calculate” button.

Want to know more? Below, we explain the history, origin and development of all the essential shoe size measurement systems.

Shoe sizes can often be confusing for non-experts. There are several shoe size systems that are used in different regions and have developed over time. Whereas the Paris point is used as the standard in mainland Europe, UK and US shoe sizes can often cause confusion. You can find out everything you need to know about the topic here.


The Paris point – it all started with a sewing machine.

In the mid-19th century, the so-called “Paris point” was established in France as a standard for a measuring shoe sizes, and this system gradually spread across Europe. The measuring system is still the same as it was back then. The Paris point is now considered the standard shoe size system in Europe and is therefore also referred to as “French size”, “European size”, “EU shoe size” or “German size”. It uses centimetres, making it a metric system. Britain is the only country is Europe that uses its own measurement system (based on inches). You can find out more about the English method for measuring length in the following chapter.

The Paris point (or European size system) probably originates from the original stitch length of the double seams of a sewing machine. The stitch equates to two thirds of a centimetre (6.67 mm).

The size system starts with a child’s size of 15 which corresponds to an inner length of the shoe of 10 centimetres, and usually goes up to men’s size 50 (33.3 centimetres). The European shoe size system includes both child and adult sizes and features a uniform system (different from the UK and US systems).

It is rare for shoes featuring the Paris point as their unit of measure to be produced in intermediate sizes (half sizes). This means that the difference between shoe sizes is always 6.67 mm.

Shoe sizes in the EU are calculated as follows:
Last length in cm (= foot length plus 1.5 cm) / 0.667.

The last is therefore always slightly longer than the wearer’s foot due to the fact that the foot moves up to 1.5 cm in the shoe when walking, meaning that this extra space is necessary. When measuring your feet, you should add 1.5 cm to the length so that you get the required space inside the shoe.

You can recognise the French shoe size when several shoe sizes have been written on the label usually, under the abbreviation “EU”, short for “European Union”.  It differs from the English and American shoe length measurement


English  – it all started with barleycorn

The English system for measuring length is the oldest official shoe size system in the world. Unlike the continental European metric system for measuring, the English method for measuring length is not based on centimetres, but, as typical in Anglo-American countries, on inches.

Throughout the Middle Ages, it was customary to orient oneself based on natural dimensions (e.g. fingers, feet, cubits) because measuring instruments (e.g. rulers, tape measures) were expensive and unavailable in everyday life. In the year 1324, the King of England Edward II introduced a standard for measuring length. He opted to use barleycorn as the smallest unit of measure in Britain. He stated that three barleycorns placed lengthways next to each other equalled one inch. One inch is equal to 2.54 cm in metric terms. If the person carrying out the measurement did not have any barleycorns available, they were also able to use their thumb width. Men from Northern Europe generally have a thumb width of three barleycorns, i.e. 2.5 cm (measured over the fingernail).

Even today, 1/3 of an inch (8.46 mm) in English is named a “barleycorn”, in line with its origins. This is how the English system for measuring shoes came about. Each full shoe size was one barleycorn larger than the previous one (8.46 mm). Half shoe sizes (4.23 mm) were introduced around 1880 to provide better fits.

In contrast to the Paris point, a system where all shoe sizes are numbered uniformly, the English method of measuring length distinguishes between adult and child sizes (making it more complicated):

Child sizes start at the smallest practicable size of 12 barcleycorns. It corresponds to an interior shoe size of 10.16 cm and is classified as the UK child size 0. The child size 13 ½ (approx. 22 cm interior length) is, followed by the adult size 0, with the largest men’s size being 14 (=33 cm).

English shoe sizes (adult sizes) are calculated as follows:
Last length in cm (= foot length plus 1.5 cm) divided by 2.54 x 3 - 25.

Last length in inches x 3 - 25

You can also recognise the English shoe size when several shoe sizes have been written on the label usually under the abbreviation “UK”, short for “United Kingdom”. The English size is different from the US method for measuring length. You can find more information about the US method for measuring length below:

To ensure that you always get the optimum shoe size when shopping at Sioux, we have also adopted the English system of half sizes (intermediate sizes) for our collections. We produce individual models up to size 15 so that those with big feet can find the right shoes when shopping with us too.


The US method of measuring is similar to that in the UK, with a few differences.

The US shoe size system (US size) is based on the UK system. It was introduced in the mid-19th century, but differs from the its English counterpart in that the scale starts at 3 11/12 inches, not at 4 inches. The child size 0 is equivalent to the Paris point of 15.

Similar to the UK system, the system also incorporates half sizes. The graduation between sizes is always 4.233 mm, just like the UK system.

US shoe sizes (men’s sizes) are calculated as follows:
Last length in cm (= foot length plus 1.5 cm) divided by 2.54 x 3 - 24.

Last length in inches x 3 - 24.

Note: when calculating women’s sizes, 23 is subtracted as part of the formula (not 24 as stated above).

The US shoe size system is often used for trainers that are sold in Europe (Germany). The US and UK methods for measuring length differ from one another in terms of men’s sizes by two sizes, i.e. the US size 10 is equivalent to the UK shoe size 8 (which corresponds to 42 in the French system). In terms of women’s sizes, the difference is only one size, i.e. the US women’s size 5 is equivalent to the UK size 4.

In addition, trainers are generally much smaller than common outdoor shoes. This means that you have to buy trainers 1.5 (UK/US) or 2.5 sizes (French size) bigger than you would buy common outdoor shoes.

If several shoe sizes are displayed on the label of the shoe, the US size is usually indicated by the abbreviation “US” (for United States). The whole system may sound a little confusing, and that’s because it is. The table below makes the system clearer.


When do oversized and undersized shoes come into play?

The standard adult sizes (European industry standard) usually ranges in terms of women’s shoes from UK 3.5 (EU 36) to 8.0 (EU 42) and in terms of men’s shoes from UK 6.5 (EUR 40) to UK 12 (EU 45).

However, at Sioux, we manufacture men’s shoes up to UK size 15 (EU 50 1/2) and women’s shoes up to UK size 10.5 (EU 45) so that those with bigger feet can get the shoes they desire too.

Sizes exceeding regular adult sizes (women’s sizes from 8.5 and men’s sizes from 12.5) are referred to as “outsizes” or “large sizes”; many online stores sell these sizes in special categories in order to make it easier for customers to search for these shoes.

Shoe sizes smaller than the industry standard are referred to as “sub-sizes” or “small sizes”.


How do I choose the right size when buying shoes online?

Shoppers buying shoes  online want to choose the right shoe size during their first order. By following the tips below, you can avoid making the wrong purchase. Making a mistake when purchasing means that you end up having to return the product. This creates more work for both the customer and distributor. Returns are also bad for the environment since products are sent on long transport routes.

So what can you do to make the shoes you order online likely to be ones that you will want to keep? You can either choose the correct size yourself, or simply pick up a couple of your favourite pairs of shoes and check what size they are.

However, it’s important that you don’t end up comparing apples with pears! For example, do not use trainers (sports or running shoes) as a point of comparison if you are looking to buy normal outdoor or leisure shoes. Trainers are not only often categorised based on US sizes but also have completely different sizes (up to two French sizes or a UK size smaller than the size actually printed).

It is therefore best to use common outdoor shoes or leather shoes that you find on your shoe rack. If both pairs of shoes on your shoe rack fit you well and are the same size according to the label, you can assume that this will be the correct size to choose when you make your next order. If the two pairs you choose have different sizes (which are similar), it is likely that an intermediate size would offer the best fit. It would therefore be wise to order two pairs of shoes in the respective size in each size online.

When it comes to choosing the right size and fit, it is, of course, best to buy the shoes in person from a local retailer. This way, you can try on the shoes, try them out and be sure that you’ve chosen the right option. The fit of the shoe not only refers to the shoe size, but also the width of the shoe. Furthermore, the lasts and processed materials have a great influence on the fit and comfort of the shoe. All of these factors are best determined in store.

Find out here how to measure your shoe width.

Disclaimer: please note that shoe sizes may vary depending on the manufacturer and model. So, even though the conversion is accurate, you may find that your selected shoe model is too big or small for your feet, and one size smaller or larger may be more comfortable. Please note that the shoe size calculator and shoe size chart is not suitable for trainers as these are made differently. Find more on this in the following text. Our shoe size calculator and shoe size chart gives you an overview of the international shoe size measurements (English shoe size, French shoe size, German shoe size and American shoe size) and explains to you the origin, method of calculation and meaning. Although we carefully research our articles on shoe sizes, we cannot guarantee the comprehensiveness and accuracy of the information and statements contained within them. We ask for your understanding on this.

Shoe size table:

Foot length in cm D / EU shoe size UK shoe size US ladies shoe size US men's shoe size
22,2 cm 35 3 4 1/2 -
22,6 cm 36 3 1/2 5 -
23,1 cm 37 4 5 1/2 -
23,5 cm 37 1/2 4 1/2 6 -
23,9 cm 38 5 6 1/2 -
24,3 cm 39 5 1/2 7 6 1/2
24,8 cm 39 1/2 6 7 1/2 7
25,2 cm 40 6 1/2 8 7 1/2
25,6 cm 41 7 8 1/2 8
26,0 cm 41 1/2 7 1/2 9 8 1/2
26,5 cm 42 8 9 1/2 9
26,9 cm 42 1/2 8 1/2 10 9 1/2
27,3 cm 43 9 10 1/2 10
27,7 cm 44 9 1/2 11 10 1/2
28,1 cm 44 1/2 10 11 1/2 11
28,6 cm 45 10 1/2 12 11 1/2
29,0 cm 46 11 - 12
29,4 cm 46 1/2 11 1/2 - 12 1/2
29,8 cm 47 12 - 13
30,2 cm 48 12 1/2 - 13 1/2
30,6 cm 48 1/2 13 - 14
31,0 cm 49 13 1/2 - 14 1/2
31,4 cm 49 1/2 14 - 15
31,8 cm 50 14 1/2 - 15 1/2
32,2 cm 50 1/2 15 - 16


Moving with light-footed ease came naturally to the North American Indians for millennia – and means one thing above all else for Sioux: ultimate comfort. This is the essential difference between German footwear manufacturer Sioux and other shoes. The famous moccasin feeling can only be truly felt on the feet when the craftsmanship is accomplished by hand. Sioux prides itself on offering a perfect fit and premium comfort.


As the foot performs a rolling motion when walking, it bears your weight in various areas and thus changes shape  in doing so. The hallmark of a perfect-fitting shoe is that the toes and the foot itself have enough space within the shoe throughout this rolling motion and that the heel experiences sufficient grip. When a shoe fits, the heel does not slip out of the back of the shoe, and the shoe sits so perfectly in the midfoot area that the foot is supported – and is unable to slip forwards – hence the shoe pinching.


Statistically speaking, the average shoe size of a German man is 42 exactly, which was also the case 40 years ago. Although people are clearly getting taller, it cannot be assumed that their feet are getting longer. When talking about “shoe size”, most people understand the length of the shoe/foot, even though the term also refers to the width.


Basically, working out your shoe size is perfectly simple. To measure it, you need a sheet of paper, the correct mathematical formula, a tape measure/ruler, a pocket calculator and, of course, your feet.


To make sure you get a perfect-fitting shoe, the right shoe size is not enough on its own. The shoe width, which defines the circumference of the forefoot, is no less important.


It is not only the correct shoe size (i.e. length), but also the correct shoe width that determines the comfort of a shoe. Find out how to measure your own shoe width here.