Japan Uses Centimeters for Shoe Size. Why Fit Still Isn’t Solved.
26.0 cm feels precise. In Japan, shoe sizing begins with a number shoppers can immediately understand: a measurement in centimeters.
That clarity is valuable. It removes much of the conversion friction created by competing regional size systems. But it does not answer the commercial question that matters most at the product page or fitting floor:
Will this specific shoe fit this specific foot?
What a centimeter size tells us
The centimeter-based approach is a strong foundation because it keeps the reference close to the foot itself. ISO 9407:2019 describes Mondopoint as a footwear size designation and marking system based on defined measurements of the foot that the footwear is intended to fit.
In other words, the size mark is a way to communicate an intended foot measurement. It is useful, understandable and far more direct than asking shoppers to mentally convert between unrelated labels.
But a size mark is not a full three-dimensional description of the shoe.
Why 26.0 cm can still fit differently
A shoe has more geometry than length. Fit is also shaped by:
Width and girth: the room available around the forefoot and midfoot.
The last: the form that influences the shoe’s toe, arch and heel shape.
Inner volume and construction: including height, padding, materials and structure.
Category-specific design: a running shoe, court shoe, outdoor shoe and dress shoe are built for different movements and constraints.
ASICS’ official Japan fitting guide makes this distinction concrete. It explains that the last strongly affects fit and describes width categories including Narrow, Standard, Wide and Extra Wide, with category-specific last variations. Its separate size guide also notes that conversion can differ by shoe type and that width guidance is an estimate rather than a complete fit guarantee.
None of this makes Japan’s centimeter system inadequate. The opposite is true: it gives the market a clear measurement language. The remaining gap is product-level information.
The commercial gap is not conversion. It is matching.
Traditional size guidance asks the shopper to move from one label to another: from a measured foot length to a nominal shoe size, or from one regional system to another.
Fit intelligence asks a different question. It compares information about the actual foot with information about the actual shoe model.
That shift matters for footwear brands and retailers because a shopper can understand a size chart perfectly and still be uncertain about the product in front of them. The uncertainty appears at the moment of purchase:
Is this model narrow in the forefoot?
Does the toe shape suit this foot?
Should the shopper choose the same centimeter size as usual?
If two nearby sizes could work, which one better matches the shopper’s preferred feel?
A generic chart cannot resolve those questions on its own. The answer has to be tied to the model.
From size label to fit recommendation
The useful recommendation emerges when two datasets meet:
Foot data — such as length, width, shape and fit preference.
Shoe inner data — model-specific measured dimensions and fit characteristics.
The output is no longer simply “26.0 cm.” It becomes “the best size for this customer in this product.”
Where Perfitt fits
Perfitt adds this product-specific layer across online and offline channels.
PerfittSize supports e-commerce by combining customer foot information with measured shoe-inner data to recommend a size for the individual product.
PerfittOnsite brings foot measurement and product recommendations into stores, events and other physical customer touchpoints.
The goal is not to replace Japan’s centimeter sizing. It is to build on that precise language with a more precise relationship between person and product.
Experience the difference at FaW TOKYO
Perfitt will demonstrate PerfittSize and PerfittOnsite at the 30th FaW TOKYO Autumn, held October 7–9, 2026, 10:00–17:00 at Tokyo Big Sight.
Visit West Hall, Booth A26-2 to experience the path from foot measurement to product-specific size recommendation.
Explore Perfitt Japan and plan your visit →