Quick brief
What to know before you calculate
A short read on the assumptions, trade-offs and definitions that shape the answer.
- Measure both feet and use the longer foot.
- Growth room is added before estimating the shoe size.
- A calculator gives a starting size, not a final fitting decision.
Measure the foot on a flat surface
Ask the child to stand with weight on both feet, then measure from the heel to the longest toe. Measure both feet because one can be slightly longer. Use millimetres where possible, since small differences can matter when sizes are close.
Add sensible growth room
Children's shoes usually need some extra space beyond measured foot length. Around 10 to 12 mm is a common starting point, but toddlers, school shoes, sports shoes and narrow styles can need a closer fit check. Too much room can make the shoe unstable.
Use size estimates carefully
UK and EU children's shoe sizes are not perfectly standard across every brand. A calculator can narrow the size range, but brand charts, fitting gauges and the child's comfort should decide the final purchase.
Check width and heel hold
Length is not the whole fit. The shoe should hold the heel securely, avoid pressure across the widest part of the foot and allow toes to move. Socks, insoles and shoe shape can all change the feel of the same printed size.
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