Kids' Shoe Size: UK to Japan
This page converts kids' shoe sizes from the UK system to the Japan system. Instead of mapping one country's number straight onto another's, the tool uses foot length in centimetres as an intermediate reference — which is how each size is actually defined. That avoids the rounding errors that creep in when you map system to system, and gives you the closest possible match.
For example, a kids' UK 1 converts to a Japan 20.6 — a foot length of about 20.6 cm. Children’s feet grow fast, so it is worth re-measuring every few months.
The kids' sizes in this chart span a foot length of roughly 16.5 to 23.5 cm. Keep in mind that real-world fit varies by brand, last and material: a running shoe and a dress boot in the same nominal size can feel different. If you are between two sizes, sizing up is usually the safer choice — especially later in the day, when feet are slightly more swollen.
Shoe size converter
Convert to Japan
20.6
Foot length: 20.6 cm
Full conversion table
| UK | Japan | cm |
|---|---|---|
| 9.5 | 16.5 | 16.5 |
| 10.5 | 17.1 | 17.1 |
| 11 | 18.1 | 18.1 |
| 12 | 19.1 | 19.1 |
| 13 | 19.7 | 19.7 |
| 1 | 20.6 | 20.6 |
| 2 | 21.6 | 21.6 |
| 3 | 22.2 | 22.2 |
| 4 | 23 | 23 |
| 5 | 23.5 | 23.5 |
How to measure your foot at home
To find your size with confidence, measure your foot rather than relying on the number you usually buy. Stand on a sheet of paper with your heel against a wall and your weight evenly spread, then mark the tip of your longest toe. Measure the distance from the wall to that mark in centimetres, and repeat for the other foot.
Use the measurement from your longer foot — almost everyone has one foot slightly bigger than the other — and match it against the centimetre column in the chart below. Measure in the afternoon and wear the type of sock you plan to use; a couple of millimetres can change the recommended Japan size.
Frequently asked questions
How do I convert a kids' UK size to Japan?
Select your UK size in the calculator and you will immediately see the equivalent Japan size for kids' footwear. The conversion is based on foot length in centimetres rather than a direct formula between systems, so it is as accurate as possible.
Is the conversion the same for men, women and kids?
No. The same number maps to different foot lengths depending on the category, which is why we provide separate charts for women, men and kids. Make sure you are using the kids' chart for your conversion.
I calculated my size but the shoes do not fit — why?
Sizes are a starting point; final fit depends on the brand and last. If one brand consistently runs tight for you, try going half a size up. Always check the manufacturer's own size guide where it is available.
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