A 210 mm foot is the smallest size the women's grid carries, below where most European ranges begin and into territory shared with older girls' shoes.
CM to US conversion
Women's US comes from the centimetre length by subtracting 17 flat, so 24 cm is US 7 and 27 cm is US 10 with no drift. The foot measurement leads and the US size follows, which keeps whole-centimetre feet on whole US numbers and avoids the rounding that dogs the EU pair. Going straight from a measured centimetre length to US is the most reliable route, since it skips the last-length assumptions the EU scale adds.
At this size, CM to US
One size up from 21 cm, US moves 0.5 to US 4.5 while the metric length rises 0.5 to 21.5 cm. Both 21 cm and US 4 are whole numbers here, so nothing rounds. For 21 cm, the US column here runs US 4, US 4.5, US 5, 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 21 34 4 2 21.5 34.5 4.5 2.5 22 35 5 3 22.5 35.5 5.5 3.5
Frequently Asked Questions Does 21 cm round up or down in US? EU 34, US 4 and UK 2 are all whole here, so a rounding choice is rare; when a foot sits between sizes, the larger one with a snugger lace beats a short toe box.
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Note Based on Mondopoint standard (foot length in mm) Women's sizing differs from men's by approximately 1.5 US sizes Heel height affects fit - measure standing Shoe sizes can vary by brand and style See a number that looks off? Report an error on this page.