Japanese kids to US shoe size
Useful when a Japanese or Korean store lists sizes in cm and you know the US size.
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How to use it
- Enter jp size.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
JP size = foot length in cm. Last length = foot length + 2/3 in. US child size = 3 × last length (in) − 11.75; Y sizes continue the same scale after 13.5C.
Example
Inputs: JP size = 15 cm. Result: US size: 8C; Exact value on the US scale: 7.97; Last length: 16.69 cm.
Limits and caveats
- The last is taken as 2/3 in (about 17 mm) longer than the foot; some European makers add only 13 mm.
- Brands differ by half a size to a full size, so check the brand chart before you buy.
Questions about this tool
What US size is JP 15?
The exact value is 7.97 on the child scale, so the tool shows 8C.
Why is the exact value below 1 with a 1Y result?
The Y scale restarts after 13.5C, so 0.87 means just under 1Y.
Are Korean sizes the same as Japanese?
Korean sizes give the foot length in mm, so 150 equals JP 15.