Choosing Kids' Shoe and Clothing Sizes — C/Y Labels, Height-Based Sizes, and Growing Room
The C (Child) and Y (Youth) labels on children's shoes and UK kids' sizes, height-based children's clothing sizes (90, 100, 110) and 2T/3T/4T, and how much growing room to allow.
Children's sizes are tricky for two reasons. Each country has its own children's numbering scale, and children grow fast, so a size that fits now will be too small in a few months.
Children's shoes: start with foot length
As with adults, measuring foot length is the starting point. Stand the child with their heel against a wall and mark the tip of the longest toe. For young children who can't stand still, taking out the shoe insole and placing their foot on it also works. Korean sizes state this foot length in 5 mm steps.
C and Y, and UK kids' sizes
| Label | Meaning | Example |
|---|---|---|
| US 4C–10C | Infants and toddlers (C = Child) | 10C ≈ foot length 160 mm |
| US 10.5C–13.5C | Children | 13C ≈ 190 mm |
| US 1Y–7Y | Youth (Y = Youth) | 1Y ≈ 200 mm |
| UK 0–13.5 | UK children's | Adult 1 follows 13.5 |
In the US, counting starts again from 1Y after 13.5C. If you buy based only on ‘US 2’, you may confuse a baby shoe (2C) with a primary-school child's shoe (2Y), so always check the C or Y. The correspondences above are the common pattern in major sportswear brands' children's size charts and may differ by about half a size between brands.
How much room to allow
- Generally, allow about 1 cm beyond the foot length.
- Buying much bigger shoes ‘so they last longer’ lets the foot slip inside the shoe, making walking unsteady and falls more likely.
- Children often can't express discomfort well. After putting the shoes on, press the toe end with your thumb and check that about one finger fits behind the heel.
- During periods of fast growth, it is good to measure again every two to three months.
Children's clothing: height is the basis
Korea and Japan label children's clothing with height directly (110 = clothing for a height of about 110 cm). Europe uses heights in 6 cm steps (98, 104, 110, 116), the UK uses age ranges such as ‘4–5 years’, and the US uses 2T, 3T, 4T (T = Toddler) followed by 4, 5, 6, 7 ….
| Korea, Japan (height) | Europe (height) | UK (age) | US |
|---|---|---|---|
| 90 | 86–92 | 1½–2, 2–3 | 2T–3T |
| 100 | 98–104 | 3–4, 4–5 | 4T |
| 110 | 110 | 5–6 | 5 |
| 120 | 116–122 | 6–7, 7–8 | 6–7 |
| 130 | 128–134 | 8–9, 9–10 | 8–10 |
UK and US age labels assume the average height for that age, so for children who are tall or short for their age it is more accurate to choose by height rather than age. The converter recommends the nearest Korean size at or above the child's height.
Ages are for reference only
The ages in the SIZE ATLAS charts are approximations based on the middle of growth records. They are not a tool for judging a child's growth or development and do not replace a diagnosis. If you are concerned about growth, consult a professional such as a pediatrician.
The full correspondence chart is in the kids' size chart.
Size systems are approximate correspondences based on national standards and industry practice, and can differ by half to one size depending on brand, product and fabric. Always check the brand's own size chart before buying.