Japanese shoe sizing is in centimetres, which sounds straightforward until you realise that the centimetre measurement is a nominal size, not a direct measurement of your foot. A size 26.5 shoe is not 26.5cm long inside. The actual internal length varies by brand, by model, and by the shape of the last the shoe was built on. This guide explains what the numbers mean and how to use them.
What the Japanese cm size actually means ¶
The Japanese Industrial Standard for footwear defines shoe size in centimetres based on the length of the foot, not the shoe. A size 26.5 is designed for a foot that measures approximately 26.5cm from heel to the tip of the longest toe. But the internal length of the shoe will be longer than that. Usually by 1 to 1.5cm. To allow for toe movement. The problem is that 'usually' is doing a lot of work in that sentence. Some brands run short, some run long, and the only way to know is to try.
Why US and EU conversions are unreliable ¶
Conversion charts exist, but they are approximations based on average lasts, and lasts vary enormously. A US men's 9 is often listed as 27cm in Japanese sizing, but we have seen the same model in US 9 run anywhere from 26.5 to 27.5 depending on the brand. EU sizing has the same problem. We measure both feet in centimetres at every fitting and use that as the starting point, then adjust based on the specific model's last shape.
The two-feet problem ¶
Most people have feet that differ in length by at least 3-4mm. Some people have a difference of a full centimetre or more. Standard advice is to fit to the larger foot, but it is more nuanced than that. If the difference is large, the fit of the smaller foot matters too. A shoe that is too long on the smaller foot can cause the foot to slide forward and create pressure on the toes. We look at both feet and sometimes recommend different lacing patterns for each side to compensate.
Width and last shape ¶
Japanese sizing does include width designations (E, EE, EEE, EEEE), but most imported brands do not use them. What matters in practice is the shape of the last: some lasts are narrow through the midfoot, some are wide through the toe box, some have a high instep. We note the last shape of every model we carry and can tell you before you try it on whether it is likely to work for your foot shape.
Sizing is the part of shoe buying that most shops rush through. We do not. Come in, bring your current shoes, and we will measure properly. It takes about five minutes and it changes everything after that.