EU 33 reaches US 13, the last number before the US children's scale restarts at 1 for bigger feet, so 13 here is a large child's size, not an adult one.
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 20 cm, UK moves 0.5 to UK 12.5 while the metric length rises 0.5 to 20.5 cm. Both 20 cm and UK 12 are whole numbers here, so nothing rounds. For 20 cm, the UK column here runs UK 11.5, UK 12, UK 12.5, 4 sizes below the point where the UK count rolls over to UK 1.
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 18.5 30 11.5 10.5 19 31 12 11 19.5 32 12.5 11.5 20 33 13 12 20.5 33.5 13.5 12.5 21 34 1 13 21.5 35 1.5 13.5
Frequently Asked Questions Does 20 cm round up or down in UK? Round up for growth, but do not read the coming US 1 as smaller: it sits one length above US 13, and foot length, not the number, tells you which is bigger.
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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.