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.
UK to US conversion
UK and US kids' sizes sit one number apart, UK 10 to US 11, until the US scale resets two steps before the UK one. Between a 210 and 215 mm foot the pair breaks: US has already restarted at 1 while UK still reads 13, a 12-number gap that closes once UK resets too. Add one to the UK number everywhere except that short window, where the two scales briefly disagree by a full cycle.
At this size, UK to US
One size up from UK 12, US moves 0.5 to US 13.5 while UK rises 0.5 to UK 12.5, holding their spacing. Both UK 12 and US 13 are whole numbers here, so nothing rounds. For UK 12, the US column here runs US 12.5, US 13, US 13.5, 2 sizes below the point where the US count rolls over to US 1.
Size Chart UK EU US CM 10.5 30 11.5 18.5 11 31 12 19 11.5 32 12.5 19.5 12 33 13 20 12.5 33.5 13.5 20.5 13 34 1 21 13.5 35 1.5 21.5
Frequently Asked Questions Does UK 12 round up or down in US? 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.