Kids' Clothing Size Conversion: UK, US and EU

Kids' clothing size conversion starts with one rule: US and UK sizes follow age, while EU sizes follow height in centimeters. The EU number is the tallest height the garment fits, so a child's height is the most reliable starting point.

The chart below comes from a published conversion chart. It is an example chart, so check each brand's own size guide. If you run a store, the same problem is why AI size recommendation for fashion stores is built around a store's own sizes, not a generic table.

How do age and height sizes differ?

US, UK and Australian kids' sizes are based on age. European sizes are based on height. According to the Size.ly children's size chart (checked November 2026), the EU number is the tallest height the garment suits, so a size 140 suits a child up to 140 cm.

Age is a guide, not a measurement. Children of the same age can differ a lot in height, which is why height-based sizing is often steadier across brands.

What does the conversion chart look like?

This table is drawn from the same Size.ly chart, checked November 2026:

Age	US	UK	EU	Height (cm)
About 2	2T	24 months	92	86 to 92
2 to 3	2T to 3T	2 to 3	98	92 to 98
3 to 4	4T	3 to 4	104	98 to 104
4 to 5	5	4 to 5	110	104 to 110
5 to 6	6	5 to 6	116	110 to 116
6 to 7	6X to 7	6 to 7	122	116 to 122
7 to 8	7 to 8	7 to 8	128	122 to 128
8 to 9	8	8 to 9	134	128 to 134
9 to 10	10	9 to 10	140	134 to 140
10 to 11	10 to 12	10 to 11	146	140 to 146
11 to 12	12 to 14	11 to 12	152	146 to 152

The "T" in a US size means toddler. Some European brands use double sizes, such as 98/104, which cover two height steps, per the same source.

How do you pick a size step by step?

Use this method when you are buying across countries:

1. Measure your child's height in centimeters, without shoes, against a wall.
2. Find that height in the chart and read the EU size.
3. Read the US or UK size in the same row.
4. If the child is between sizes, size up for room to grow. Size.ly suggests this too.
5. Check the brand's own chart, since cuts vary.

Worked example: a child is 120 cm tall. That falls in the 116 to 122 band, so the EU size is 122, the US size is 6X to 7, and the UK size is 6 to 7.

How do you measure a child's height at home?

Accurate height makes the chart far more useful. You need a wall, a flat book and a tape measure.

1. Have the child stand straight against a wall with bare feet together.
2. Ask them to look ahead, with their chin level.
3. Rest the book flat on top of their head and mark the wall under it.
4. Measure from the floor to the mark, and write it down in centimeters.

Measure again every few months, because children can move up a size quickly. Keep a note on your phone with the date and height, so you can compare against the chart when you shop.

If the child is wearing thick socks, shoes or a hairstyle that adds height, remove or flatten them first. A small error can push you into the next size.

Why do kids' sizes vary so much between brands?

Brand cuts differ, and age labels cover children who grow at different rates. Size.ly's notes say that measuring a child's height is more reliable than relying on age.

This is similar to adult clothing, where UK and US numbers can mislead. Our guide to bra size conversion shows how one body can carry different labels, and the guide to men's suit size conversion covers suits.

What should store owners show on kids' product pages?

Show age, height in centimeters and the garment's cut together. Add a short fit note, such as "roomy, size down if between sizes." If you ship abroad, list the matching sizes for each market.

Local sizing habits also differ. Our guide to Nigerian clothing sizes vs UK sizes shows how labels differ for shoppers there. For adult fashion, a store's own chart plus a size scan reduces guesswork.

FAQs

Is UK kids' sizing the same as US?

Both follow age, but the labels differ. The US uses forms such as 2T and 6X, while the UK uses years and months.

What does EU size 128 mean?

It means the garment fits a child up to 128 cm tall, per the Size.ly chart. The usual height band is 122 to 128 cm.

Should I buy by age or height?

Buy by height when a height is listed, and compare it with the brand's chart. Age is only a rough guide.

What if my child is between two sizes?

Size up for room to grow, unless the garment is tight or fitted. Check the brand's fit notes first.