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What does this converter do?
Children size converter: US to EU kids clothing sizes. Free children size converter with the formula shown - runs entirely in your browser, no signup.
- EU sizes are height in cm; US/UK are age labels that assume median growth.
- For shoes, children's US sizes step by last length: toddler 10 = EU 27 = 17 cm last.
- Size up rather than fit exactly — children's garments are cut with 6-10 cm of grow room at the labeled size.
How this calculator works
Formula
Children's clothing runs by height (EU cm) or age (US/UK months-years). Height is the reliable axis: an EU 116 = US size 6 = about 6 years old on average, but a child 110-116 cm tall spans 4 to 7 years.
Sources
Sources support the method, terminology, or planning context. Editable assumptions remain your responsibility.
Assumptions to verify
- Manufacturer charts vary; conversion outputs are the standard-mapping midpoint.
- Measurements are body measurements unless the tool labels them as garment measurements.
- Between-size results round per the rule stated in the FAQ.
Frequently asked questions
Should I buy by age or by height?
Height, when the chart offers it (EU labels always do). Age labels assume a median child; the spread around that median is 2+ years by age 6.
What if I fall between sizes?
Round the direction that matches use: clothing and shoes generally round up.
Cite this tool
BoringToolsKit. “Children Size Converter.” boringtoolskit.com/children-size-converter/ (reviewed 2026-09-20). Free to reference in articles, syllabi, and answer posts with a link.
Privacy: Inputs and results stay in this browser. Conversion runs locally in your browser; review the output before relying on it.
Worked example: converting a US 7
A parent with a US size 7 pair of kids trousers that fits well wants the EU equivalent. The chart inside the calculator maps US 7 to EU 122, and EU kids sizes in this range are simply the child's height in centimetres, so the conversion is one lookup: US 7 becomes EU 122, usually printed as 122 on the label. A child wearing US 7 should measure roughly 122 cm tall.
You can check the chart's internal logic against its rows. Every step from US 4 to US 14 raises the EU value by exactly 6 cm: 104, 110, 116, 122, 128, 134, 140, 146, 152, 158, 164. The Hatley/Little Blue House chart this data comes from spaces each kids size one height grade apart, about 6 cm of growth per size. Knowing one row derives its neighbours: US 8 must be 122 + 6 = 128, and US 6 must be 122 - 6 = 116. A bigger jump works the same way: US 12 is two rows above US 10, and 140 + (2 x 6) = 152, which matches the table. The mapping is linear by construction, so there is no rounding or curve to get wrong.
Practical reading of the example: a child measuring 119 cm sits between grades. The convention is to round up to EU 122 (US 7), because children grow into the larger height grade long before growing out of the smaller one. EU 116 (US 6) only makes sense near the top of that band, around 115 to 116 cm, where the smaller size still fits.
Where this chart stops being the right tool
The table covers exactly eleven rows, US 4 through US 14, mapping to 104 through 164 cm. Enter US 3.5 or below, or US 14.5 and above, and the calculator refuses rather than guessing: anything outside 4 to 14 returns the check-the-input message. That boundary matters because US 14 sits near 164 cm, the point where most brands split kids sizing from adult sizing, and EU adult labels use a different numbering system entirely.
Brand variance is the largest real error source. 122 cm is the chart's answer for US 7, but European labels can vary by up to one full grade (6 cm) between makers: a 122 from one brand may fit like a 116 or a 128 from another. Slim, regular, and plus cuts add width differences a height number never captures, so treat the conversion as a starting point for the size tag, not a fit guarantee.
Other systems do not line up with the table. UK kids sizes run one to two rows off this US scale, and EU sizes below 104 cm are labelled in months (EU 98, EU 92) rather than continuous height grades, so a baby at US 4 equivalent height still cannot be converted here. Age is the weakest proxy of all: a 7-year-old can measure anywhere from about 115 to 130 cm, spanning three grades. Measure standing height without shoes and match the centimetre number, not the age.