Kids next shoe size calculator
Useful when buying a size up to last longer, or to see how much bigger the next size really is.
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How to use it
- Enter us size and half sizes up.
- 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
Each US half size adds 1/6 in (4.233 mm) to the last. New EU size = 1.27 × (new US + 11.75).
Example
Inputs: US size = 8C, Half sizes up = 2. Result: New US size: 9C; Added length: 8.47 mm; New EU size: 26.
Limits and caveats
- A shoe far too big lets the foot slide, so going up more than a half or full size is rarely wise.
- Brands differ by half a size to a full size, so check the brand chart before you buy.
Questions about this tool
How many mm is a full size?
A full US or UK size adds 1/3 inch, 8.47 mm.
What comes after 13.5C?
The next size is 1Y, as the scale moves on to big kids.
Should I buy a size up to last a year?
Half a size up is usually fine; much more can cause trips, so measure every two months.