Shoe size converter
Stand on a sheet of paper with your heel against a wall, mark the end of the longest toe, and measure. Do it late in the day with the socks you will wear, and measure both feet. Most people have one that is a few millimetres longer, and the shoe has to fit that one. Adding five to ten millimetres of toe room on top is normal for walking shoes and essential for running.
Shoe sizing is not standardised between brands and differs markedly between sports and dress styles. Foot length in centimetres is the only reliable common reference, and even that is measured against the shoe last rather than your foot.
The four sizing systems are unrelated scales laid over the same quantity, foot length. A 26 cm foot is EU 41.5, UK 7.5, US men 8.5 and US women 10. Japanese sizing is the foot length in centimetres itself, which makes it the only one of the four you can read without a conversion.
How to convert shoe sizes
The scales count in different units, from different zeros, against different things. EU sizing counts Paris points, a unit of two thirds of a centimetre inherited from French shoemaking. UK sizing counts barleycorns, a third of an inch, from a zero set 25 barleycorns below size zero. US sizes are the UK scale shifted, and shifted by different amounts for men and women, which is why the 1.5-size gap between US men and US women is a labelling convention rather than a fact about feet. None of the four was designed to interoperate with the others.
All of them also size the shoe rather than the foot. A last is longer than the foot it is built for, and the difference, the toe allowance, is what makes a size wearable. This converter uses 15 mm, which is a common figure and a middle-of-the-road one. Manufacturers use their own, from around 10 mm on a close-fitting dress last to 20 mm or more on a running last, and that alone explains a large part of why the same nominal size fits differently between two boxes on the same shelf.
One system does try to solve this. ISO 9407 defines Mondopoint, which labels footwear by the length and width of the foot it fits, in millimetres, instead of by a national scale. It is standard in ski boots, skates and military footwear and it is what Japanese sizing amounts to in practice, but it never displaced EU or UK numbering in general retail.
So treat every converted figure here as a starting point. Foot length in centimetres is the only quantity that means the same thing everywhere, which is the reason this panel routes every conversion through it instead of translating one national scale straight into another.
What people use it for
- Buying shoes from an overseas site
- Converting a size printed on a foreign box
- Turning a US size into an EU one, on the right scale
- Measuring a growing child's feet
- Comparing a running size against a dress shoe size
Questions
About EU 42, and US men 9. The conversion varies slightly between brands because the toe allowance does.
Heel against a wall, standing with your weight on the foot, mark the end of the longest toe and measure back to the wall. Do it late in the day.
Usually not. A few millimetres of difference is common, and the shoe has to fit the larger one.
Around 5 to 10 mm for everyday shoes and closer to a thumb's width for running, on top of whatever the manufacturer already built into the last.
Because the two scales were offset from the UK scale by different amounts. It is a convention about labelling, not a measurement, which is why the US tab asks which scale your number is on.
There is no enforced standard, toe allowances vary by several millimetres, and lasts differ in width and shape as well as length. Check the brand's own chart before ordering.
ISO 9407 defines the Mondopoint system, which sizes footwear by foot length and width in millimetres. It is used in ski boots, skates and military supply, and general retail has largely ignored it.
Because it is foot length, stated plainly. It is the same idea Mondopoint formalises, and it is the reason the Japan row on this panel matches the foot length row.
Because the conversion is continuous and shoe sizes are not. UK and US sizes are sold in halves and the EU row here is rounded to the nearest half, but the UK and US rows keep a decimal so you can see which way the foot falls. A UK 8.1 means an 8 with very little room, and an 8.5 is the safer buy.