Convert a shoe size between JP, US, UK, and EU

The job

A listing says "US 9" or "EU 42" and you think in centimeters — or the reverse. Shoe size systems do not map cleanly onto each other, so the safe approach is a standard conversion row rather than mental arithmetic.

How to do it

Pick the system the listing uses, type the size (a number is enough — units like "cm" are stripped), and read the equivalent in all five systems at once.

• Japan uses foot length in centimeters; US splits into men's and women's rows; UK and EU run on their own scales.
• Half sizes like 26.5 and decimal commas (42,5) are accepted.

Worked example

Entering 26.5 in Japan (cm) reads back as US men's 8.5, US women's 10, UK 7.5, and EU 40.

Limits

The tool snaps to a standard adult table covering 22–30 cm; an in-between value takes the nearest row and is marked approximate. Brands cut the same nominal size differently and kids' ranges are not included — treat it as a starting point, and check the maker's own chart before ordering.