A 150 mm foot marks the small end of this range, a length most children reach around age three; Austrian tracking shows the foot still adding close to 1 mm a month at this stage.
CM to UK conversion
Centimetres to UK kids' sizes hold near an 8-number gap until the UK scale resets at a 220 mm foot, where the same length suddenly reads about 21 less: 18 cm is UK 10 but 22 cm is UK 1. Sizing by the millimetre length sidesteps the confusion the reset causes. Because a shoe's inside often measures shorter than its printed size, checking the internal length against the foot matters more than the UK number itself.
At this size, CM to UK
One size up from 15 cm, UK moves 0.5 to UK 7.5 while the metric length rises 0.5 to 15.5 cm. Both 15 cm and UK 7 are whole numbers here, so nothing rounds. For 15 cm, the UK column here runs UK 7, UK 7.5, UK 8, stepping a half size at a time.
Foot length vs shoe length
A CM shoe size is your measured foot length, not the space inside the shoe.
Brands add 0.5 to 1.0 cm of toe room so your toes clear the front. Japanese cm
labels already include about 1 cm of it, so a JP 24.0 measures near 25 cm
inside; an EU number instead describes the last. That built-in gap is why
conversion tables disagree.
Why one foot length gives many sizes
Size Chart CM EU US UK 15 24 8 7 15.5 25 8.5 7.5 16 26 9 8 16.5 27 9.5 8.5
Frequently Asked Questions Does 15 cm round up or down in UK? With the foot still growing, round to the larger size: the extra millimetres become fit within weeks. Aim for 12 to 17 mm past the longest toe when the shoe is on.
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Note Kids sizes transition to adult sizes around EU 38 / US 5 Children's feet grow rapidly - remeasure every 3-4 months Allow 10-15mm growing room when fitting Shoe sizes can vary by brand and style See a number that looks off? Report an error on this page.