How to convert US to Japan shoe size: footwear guide
When purchasing sneakers from Japanese makers like ASICS and Mizuno, Japanese sizing provides an intuitive reference. Unlike Western systems based on arbitrary scales, the Japanese system is purely metric.
Understanding Japan shoe size: the JIS S 5037 metric standard
The official foundation of Japanese footwear is codified under the Japanese Industrial Standard JIS S 5037:1998. Under this standard, shoe size represents the anatomical length of the foot in centimeters, or millimeters under the international Mondopoint standard. A size marked 27.0 accommodates a foot measuring 27.0 centimeters from heel to the tip of the longest toe.
A 27.0 cm footbed measures 27.0 cm regardless of whether the footwear is designed for men or women. Because American shoe sizes are segmented into distinct men's and women's scales, converting an American shoe size to Japanese numbers requires gender-specific formulas.
Core formulas: American shoe size to Japanese conversions
To approximate shoe size from an American number to a Japanese centimeter size, use these standard conversions:
- For adult American men's footwear, adding 18 to your US shoe size approximates your Japanese centimeter size. For example, US Men 7.0 + 18 = 25.0 cm (JP 25.0), and US Men 9.0 + 18 = 27.0 cm (JP 27.0).
- For American women's sizes, adding 17 to your US size gives the approximate Japanese centimeter size. For example, US Women 6.0 + 17 = 23.0 cm (JP 23.0), and US Women 7.5 + 17 = 24.5 cm (JP 24.5).
- Children's footwear in Japan increments by 0.5 cm intervals. An American toddler 6C translates to approximately 13.0 cm, while a little kid 10C corresponds to 16.5 cm.
Reverse conversions: Japan shoe size to US equivalence
International buyers translating Japanese shoe numbers to American sizes can reference these common points:
- A Japanese size 24.5 (24.5 cm) converts to an American US Women's 7.5 or an American US Men's 6.5 (European EU 38.5).
- A Japanese size 26.0 (26.0 cm) converts to an American US Men's 8.0 or US Women's 9.0 (European EU 41).
- A Japanese size 27.0 (27.0 cm) converts to an American US Men's 9.0 or US Women's 10.0 (European EU 42).
- A Japanese size 28.0 (28.0 cm) converts to an American US Men's 10.0 or US Women's 11.0 (European EU 43).
Japanese footwear brands and width standards
Foot width is just as important as foot length when ordering shoes. For detailed width measurements, consult our shoe size calculation guide. Under JIS S 5037, standard adult men's footwear in Japan defaults to 2E (EE) width, whereas standard American men's footwear defaults to D width (Medium). Japanese lasts incorporate a wider forefoot ball girth. If you have narrow feet, select D width where offered or adjust your sizing accordingly.
Measuring your foot for a Japan shoe size chart
Because Japanese sizing reflects your foot length in centimeters, a direct foot measurement provides the most accurate result. For step-by-step tracing instructions, visit our guide on how to measure foot length.