Kids Shoe Size Conversion Guide

5 min read•June 1, 2025•Reviewed: June 1, 2026

✓Reviewed by Apex Conversion Editorial Team · Last reviewed June 1, 2026

Children's shoe sizes are a world of their own. In the US, kids' sizes start at 0 (newborn) and run through size 13 before transitioning to adult sizes starting at 1Y (youth). EU and UK children's sizes follow separate scales that converge with adult sizing at different points.

Because children's feet grow fast — up to two sizes per year for toddlers — accurate sizing matters more than in adults. A shoe that is too tight causes blisters and deformity; one that is too loose causes tripping. Measuring a child's foot every few months is recommended.

US Kids to EU Size Comparison

US Kids  EU    UK Kids  Age (approx)
────────  ──    ───────  ────────────
  1C      17      1      0–6 months
  2C      18      1.5    6–9 months
  3C      19      2.5    9–12 months
  4C      20      3.5    12–18 months
  5C      21      4.5    18–24 months
  6C      22      5.5    2 years
  7C      23      6.5    2.5 years
  8C      25      7.5    3 years
 10C      27      9.5    4 years
 12C      30     11.5    5–6 years
 13C      31     12.5    6–7 years
  1Y      33      1      7–8 years
  3Y      35      2.5    9–10 years
  5Y      37      4.5    11–12 years

When Kids Transition to Adult Sizes

In the US, children's big-kid sizes run 1Y through 7Y. At size 7Y, most kids transition to adult sizing — a 7Y is equivalent to a US Men's 7 or US Women's 8.5. Girls often transition a size or two earlier than boys because female feet stop growing earlier on average.

EU sizing transitions seamlessly — EU 38 is EU 38 whether it is in the kids' or adults' range. UK kids' sizes transition to adult at about UK 6.

How to Measure a Child's Foot

Have the child stand barefoot on a piece of paper. Trace both feet and measure heel to the longest toe. Add 0.5–1 cm (a thumb's width) to allow for growth. Look up this measurement against the size chart for the target country.

Children's feet grow fastest between ages 1 and 3 (up to two sizes per year), then about one size per year until age 10–12. Measure every 2–3 months for toddlers, every 4–6 months for school-age children.

Quick Tips

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Always leave a thumb's width (about 1 cm) between the toe and the end of the shoe when fitting children.
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Toddler feet are often wide. Many EU brands offer wide fittings for toddlers.
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Hand-me-down shoes are not recommended — they mold to the previous wearer's gait and may cause problems for the new wearer.
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For online purchases, use foot length in cm as the most reliable measurement for EU and Japanese sizing.

Frequently Asked Questions

What is a US kids' size 12 in EU?

US Kids' 12C ≈ EU 30. This is approximately a 6–7 year old's size, though foot size varies greatly among children of the same age.

When do kids move to adult shoe sizes?

In the US, children move to adult sizing around size 7Y (big kids), which corresponds to a US Men's 7 / Women's 8.5. This typically happens between ages 11–14 depending on the child.

Are European children's shoe sizes smaller than American?

They use different scales, but they fit the same feet. EU 30 and US Kids' 12C both describe a shoe for a foot approximately 18.6 cm long.

Do kids' shoe sizes work the same for boys and girls?

In the US, children's sizes (infants, toddlers, and big kids) do not separate by gender — a size 5C is a size 5C. Gender-specific sizing starts when girls transition to US Women's sizes and boys to US Men's sizes.

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