UK kids to US kids shoe size
Converts UK child and junior sizes to the US scale most online stores use.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter uk 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
UK child size = 3 × last length (in) − 12; UK adult size = 3 × last − 25. US child size = 3 × last length (in) − 11.75; Y sizes continue the same scale after 13.5C. So US = UK + 0.25 on the same scale.
Example
Inputs: UK size = 5 (child). Result: US size: 5.5C; Exact value on the US scale: 5.25; Last length: 14.39 cm.
Limits and caveats
- The scales differ by a quarter size, so the larger US size is shown; some sports brands add a full size.
- Brands differ by half a size to a full size, so check the brand chart before you buy.
Questions about this tool
Why is the US number higher than the UK one?
The US child scale starts from a last a quarter barleycorn shorter, so the same last reads a quarter size higher.
What comes after UK child 13.5?
The adult scale starts at 1, which is about 1Y to 1.5Y in the US system.
Does this work for boys and girls?
Yes. Kids sizes are unisex in both systems up to the end of the Y scale.