US kids to Japanese shoe size
The JP size equals the foot length in cm, so it follows from the foot length a US size fits.
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How to use it
- Enter us 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
US child size = 3 × last length (in) − 11.75; Y sizes continue the same scale after 13.5C. Last length = foot length + 2/3 in. The JP size is the foot length in cm, rounded to the nearest 0.5.
Example
Inputs: US size = 10C. Result: JP size: 16.5 cm; Approximate foot length: 16.72 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.
- Japanese brands advise a size equal to or above the foot length, so if the foot is longer than the shown size, take the next one.
Questions about this tool
What JP size is 10C?
The matching foot length is 16.72 cm, so the tool shows 16.5.
Does the JP size include toe room?
No, it is the foot length itself and the maker builds the room into the shoe.
Does this work for Mondopoint?
Yes. Mondopoint is the foot length in mm, so multiply the result by 10.