Kids' Shoe Size by Age

Why age predicts shoe size poorly

Age charts sell shoes because they are simple, but the measured record is against them. In a study of 858 Austrian pre-school children aged three to six and a half, 69.4 percent were wearing outdoor shoes that were too short, and the shorter the shoe, the larger the child's big-toe deviation. The same research group found that only a small fraction of children had shoes with the correct inside length. Age told the parents almost nothing useful; the feet had to be measured.

Feet also vary between children of one age. Boys and girls diverge, growth spurts land at different months, and a single year of age can cover a 15 to 20 mm spread in foot length. Use age to know roughly where to start, then measure.

How fast children's feet grow

The clearest growth figures come from the Austrian Kinderfuesse project, which tracked children's feet over time:

• Ages 1 to 3: about 1.5 mm per month, near 18 mm a year.
• Ages 3 to 6: about 1 mm per month, near 12 mm a year.
• Ages 6 to 10: a little under 1 mm per month.

Japanese data agrees closely. Foot-growth tracking published by the Japan Leather and Leather Goods Industries Association and by Achilles found roughly 15 to 20 mm of growth a year up to about age three, easing to around 10 mm a year through later childhood, with a recommendation to remeasure every three to four months in the youngest children. Two national datasets, collected independently, point to the same pace.

One consequence matters for buying: a shoe bought with the maximum sensible growing room lasts only about five months at the fastest growth stage before it is too short again.

Typical foot length by age

The values below are measured averages, not sizes. A two-to-seven-year anthropometric study of thousands of children anchors the middle of the range, and the growth rates above extend it. Treat each as a midpoint with a 10 to 15 mm spread either side, then measure your own child.

Measured anchors behind the table: mean foot length is near 125 mm at one year and reaches about 185 mm (boys) and 182 mm (girls) at six, and about 191 mm at seven, in the anthropometric study; the rows between and after follow the growth rates.

The growing-room rule, 12 to 17 mm

A well-fitting children's shoe is not measured to the foot. It needs space in front of the longest toe so the foot can roll and grow. Austrian research sets the range at a minimum of 12 mm and a maximum of 17 mm: below 12 mm the toes press the end within weeks, and above 17 mm the shoe is too loose to walk in safely. A measuring gauge used in that work, plus12, adds exactly 12 mm to the foot reading so the required inside length comes out in one step.

The German WMS system used by specialist children's shops builds the same idea into the shoe, allowing 9 to 15 mm of room and advising a remeasure every three to four months. Both systems say the same thing in different words: buy for the inside length, and leave room to grow.

Why the label on the box cannot be trusted

Even a correctly chosen size fails if the shoe is mislabelled, and most are. A 2018 survey of 1,898 children's shoes found 86 percent measured shorter inside than their printed size, some by up to four sizes, so a shoe stamped EU 30 can measure around 28 inside. Buy to the inside length, not the number. The full method for checking a shoe against the foot is in the kids' shoe fit guide.

Japanese sizing runs the opposite way. A Japanese cm label already includes about 1 cm of toe allowance, so a shoe marked 18.0 cm measures near 19 cm inside, which is why a Japanese size does not convert to EU by plain arithmetic.

How to measure at home

1. Stand the child heel to a wall on a hard floor, weight on the foot.
2. Mark the longest toe, which is not always the big toe.
3. Measure heel to mark in millimetres, and do both feet.
4. Add 12 to 17 mm to get the inside length the shoe should have.
5. Compare that inside length to the shoe, not the label.

A printable foot-measuring sheet and the full method are in the foot-length guide. For the size that a given foot length maps to, use the kids' shoe charts.

Buying before back-to-school

Feet grow through summer, so a shoe measured in June can be short by September. Measure again just before the school year, apply the 12 to 17 mm room, and check the inside length of anything bought earlier. At the fastest growth stage a new pair holds its fit for only about five months, so a late-summer measurement is worth more than an early one.

Frequently asked questions

Can I buy shoes by my child's age alone?

Age gives a rough starting point, but children of one age vary by 15 to 20 mm in foot length, and studies find most age-bought shoes run too short. Measure, then use age only to sanity-check the result.

How much room should a child's shoe have?

Between 12 and 17 mm in front of the longest toe, measured as inside length. Less than 12 mm is outgrown within weeks; more than 17 mm is too loose.

How often should I remeasure?

Every three to four months for toddlers, whose feet add about 1.5 mm a month, and before each school year for older children.

Why do shoes of the same labelled size fit differently?

Most children's shoes measure shorter inside than their label, some by up to four sizes, and Japanese cm labels include about 1 cm of built-in room. The printed size is not a reliable measurement.

When do children's feet stop growing fastest?

Growth is quickest to age three at about 1.5 mm a month, then slows to about 1 mm a month from three to six, and a little under that after.