Everyone knows this problem: you search for a running shoe online or in a store, you like the look of it and/or its properties and technologies are just what you need. You order/buy the shoe, try it on and, surprise! Although it’s the same size as you always buy, this shoe doesn’t fit, so you order/buy another size and keep on trying until you find the right fit. You know what I mean, right? This raises the question: why do shoes from different brands fit differently? Why can’t a Nike 43 be the same as an ASICS 43? We’d like to explain two reasons why this happens.


Different ways to measure shoe size

The first issue is that there is no standard unit of measure for shoe sizes. Many countries have their own ranges, measuring methods and, therefore, shoe sizes. The UK, for example, uses the barleycorn method to measure shoe sizes. Barleycorn is a very old and very small unit of measurement that’s equivalent to a third of an inch, or 8.46 mm. In the US, the basic principle is the same but American sizes begin at 0, whereas British ones begin at 1. This means that a US size 15 will usually correspond to a UK size 14. Germany mainly uses EU sizes - a measurement range used by many of the countries in continental Europe. The basis for this system is the Parisian point or Parisian stitch. The idea was that, if your shoe had 38 stitches, your shoe size was 38. One Parisian stitch is ⅔ of a cm long. The measurement units change yet again in Asia, where they simply take the centimetre measurement of the foot and use this number as your shoe size. Shoes also come with a letter (A, B, C, D, E, EE, EEE, EEEE, F, G), which represents the width. All of these different measurement ranges also lead to mistakes when calculating shoe sizes and differing results. If, for example, a calculation results in a number with decimal places, some manufacturers will round the number up, while others will round it down. This can lead to a considerable difference in shoe size measurement from country to country and from brand to brand.

Different ‘lasts’ used in the manufacturing process

So-called ‘lasts’ are used during the production of a shoe. They’re basically foot-shaped templates made of wood, plastic or metal that ensure the upper and the sole fit together correctly. Both of these components are produced separately. Nowadays, the upper of a running shoe usually comprises a single piece of material. This is fitted onto the last and then glued or stitched onto the sole. Lasts are also used to ensure consistent sizing within mass production of a specific model. Brands usually use lasts that were created in their country of origin - so Nike uses US ones, unlike adidas, which uses narrower German ones. The Japanese brand ASICS uses lasts modelled after significantly smaller feet. This is why you need to go one or even two sizes up when buying ASICS shoes.

As you can see, measuring and sizing shoes is a complex and inaccurate science that differs greatly from place to place. Maybe now it’ll be less of a mystery as to why you don’t have a single shoe size for all brands, but rather have to vary it more or less depending on what shoes you’re buying. Of course, the material of the shoes and their function also plays an important role in deciding what shoe size to buy. A dressy leather shoe will obviously fit differently to a sports shoe made of soft knitted material - the latter should fit a bit looser to allow for the rolling phase, which pushes the foot forward when you run. Try out different brands and sizes and you’re sure to find the perfect fit. ;-)