UK, EU or Centimetres: Which Baby Shoe Size Should You Trust?

Three numbers on every pair and only one of them is a measurement. Here is the one to shop by, and why UK 1 is bigger than UK 13.

Every pair on this site is labelled the same way: a UK size, a foot length in centimetres and the age it typically suits. The EU equivalent lives in the size guide. Of those numbers, only one is a measurement.

The centimetres are the real number

Foot length in centimetres is the length of your child's foot. That is it. It does not depend on the brand, the country or the shape of the last. If you measure the foot at home and get 13.0 cm, that is a fact you can carry from one shop to the next.

UK and EU sizes are not measurements. They are positions on a scale, and every manufacturer maps that scale slightly differently. Two pairs both marked UK 5 can be four or five millimetres apart, which does not sound like much until you remember that a whole size at this age is about half a centimetre.

What UK sizes actually are

The UK children's scale starts at 0 and climbs to 13. Then, instead of carrying on to 14, it resets and starts again at 1 for older children. So UK 1 is not the smallest size in the range. It is one of the largest, roughly a nine or ten year old foot, and it sits directly above UK 13.

This catches out almost everybody at least once. If you are looking at a size list and UK 1 appears near UK 13, nothing is broken. That is how the scale works.

Why EU sizes look tidier than they are

EU sizes look more logical because the numbers climb without resetting. Underneath, though, they are built on an old unit, the Paris point, which is two thirds of a centimetre. That is why you see EU 19.5 and EU 26.5 on our chart. Those are not made-up half sizes, they are the points where the two systems do not line up neatly, and rounding them away would cost you accuracy exactly where a growing foot needs it.

So which one do you shop by

Centimetres. Always. Measure the foot, take the larger of the two, and match that number.

Use the UK and EU numbers for what they are good at: comparing against a pair your child already owns and wears well. If the shoes that currently fit are marked EU 22, that is useful context. It is not a substitute for the tape measure.

Then add growing room

Do not buy a shoe with an inside length equal to the foot. You want roughly one centimetre beyond the longest toe. Our chart already builds that in: the foot length column is your measurement, and the insole column is what the shoe actually measures inside.

That gap is the whole game. Too little and the shoe is outgrown in six weeks. Too much and it slides forward on every step, which is worse. And length is only half of it: width decides just as much.

When a brand gives you only one number

Plenty of listings show a single size with no centimetres anywhere. If that happens, ask before you order. Any shop that knows its stock can tell you the insole length in centimetres, and if nobody can answer that question, that tells you something too.