Kids' Shoe Sizes by Age: US, UK, EU Charts — and the 13C-to-1Y Mystery

US children’s shoe sizes run 2C through 13.5C — and then restart at 1Y, where 1Y is bigger than 13.5C. That restart confuses more parents than anything else in kids’ sizing. The full logic, the age charts, and the measuring method below; for any specific size, the kids’ shoe size converter maps US, UK, EU and centimeters instantly.

The chart: sizes, centimeters and typical ages

US	UK	EU	Foot (cm)	Typical age
4C	3	19.5	11.4	9–18 mo
6C	5	22	13.0	1.5–2.5 yr
8C	7	25	14.6	2.5–3.5 yr
10C	9	27	16.5	3.5–4.5 yr
12C	11	30	18.1	5–6 yr
13C	12	31	19.0	6–7 yr
1Y	13	32	19.7	7–8 yr
3Y	2	35	21.6	9–10 yr
5Y	4	37.5	23.3	11–12 yr
7Y	6	40	25.0	13+ yr

The converter carries every half-step and the age groups (baby/toddler → little kid → big kid).

Why the restart exists

The C and Y scales are one continuous barleycorn ladder wearing two labels — a leftover from English sizing history, where children’s sizes counted up from a tiny hand-span zero and simply rolled over at 13. Nobody designed it; everyone inherited it. EU sizing has no restart (a big kid just wears EU 33 after 32), and UK kids’ sizes shadow the US scale one step lower, rolling over the same way.

Measuring a child’s foot (the only reliable method)

1. Afternoon, standing, in socks — feet swell during the day and lengthen under body weight.
2. Heel against a wall on a sheet of paper; mark the longest toe (often the second toe).
3. Measure wall-to-mark in cm. Do both feet; fit the larger.
4. Add ~0.8 cm growing room — a thumb’s width. Enter the raw measurement in the converter; it applies the chart.

For wriggly toddlers: trace the foot on paper and measure the tracing. Check fit monthly by feeling for the big toe with the child standing — when it reaches within ~3 mm of the front, it’s time.

Why buying by age fails

Ages on size charts are population medians, and children’s feet spread widely around them: at age 4 the normal range spans roughly three full sizes. Growth is also uneven — spurts of half a size in two months, then quiet stretches. The cm measurement plus growing room sidesteps all of it, and prevents both the “outgrown in three weeks” purchase and the flopping oversized one that ruins gait.

The youth-to-women’s trick

Because youth sizes reach 7Y (≈ women’s 8.5), anyone wearing women’s ≤ 8.5 can often buy the same sneaker model in big-kid sizing at a substantially lower price: women’s size − 1.5 = youth size (a women’s 7.5 → 6Y). Width is the caveat — youth lasts run narrower.

Common mistakes

1. Reading 1Y as smaller than 13C — it’s the next size up.
2. Buying by age — measure; the age column is a sanity check, not a fitting method.
3. Fitting the smaller foot — always the larger.
4. “Room to grow” oversizing — more than ~1.5 cm extra causes tripping.
5. Hand-me-downs judged by label — worn shoes mold to the first wearer; check length and wear.

Quick summary

Kids’ US sizes climb 2C–13.5C and then restart at 1Y, which is one step bigger — the restart, not the sizes, is what confuses everyone. Skip age-based buying entirely: measure the foot in centimeters, add 0.8 cm of growing room, and let the kids’ shoe size converter find the size in every system.

Related: the adult shoe size converter · clothing sizes · cm to inches.