Use standards to estimate a toddler's shoe size from age. The recommended size is 5 for a 12- to 18-month-old child, 6 for an 18- to 24-month-old child, 7 for a 2-year-old, 8 for a 2- to 2 1/2-year-old, 9 for a 3-year-old, 10 for a 3 1/2-year-old, 11 for a 4 1/2-year-old and 12 for a 5-year-old.
What size is a 5C in UK?
US – Kids' 1C 5C
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UK 0.5 4.5
CM 7 11
EU 16 21