What age is size 4T?

The short answer

Size 4T is for a child of about 4 years. US sizes are labelled roughly by age in years, and there is no public federal height chart for them: the CPSC sleepwear rules (16 CFR 1615) list the size names only. So the height figures below come from the growth data, not from a size chart. At 4 years (48 months) the WHO median is 103 cm for boys and 103 cm for girls, and the middle 94 percent of children are inside the ranges in the table. Brands run small or large and children grow, so size up one bracket for growth room.

Use the calculator with your child's height or foot length to get exact EU/UK, US and shoe sizes.

How this was worked out

Heights come from the WHO Child Growth Standards (standing height from 24 months, so 3, 4 and 5 years are standing measures). The EU/UK size is the nearest 6 cm height size to the pooled boy-and-girl median. "4T is for age 4" is the retail labelling convention, not a measurement. Percentiles describe how children vary and are not a health assessment.

Sources and as-of date. Height data: CDC stature-for-age percentile data (2 to 20 years) (CDC growth charts) and WHO Child Growth Standards, length/height-for-age (0 to 5 years). Size designation: the EN 13402 series (ISO 3635 lineage) uses body height in centimetres as the primary dimension for children's clothing. US size names: 16 CFR 1615 and 16 CFR 1616 (CPSC sleepwear rules list sizes 9-12 months up to 14, but give no height chart). Shoe sizing: ISO/TS 19407:2023. Data files read on 2026-10-02.

Frequently asked questions

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