Measuring a child's feet sounds like it should be simple. In practice there are a handful of easy things to get slightly wrong, and they have real consequences: a shoe that fits in the shop and is tight three months later, or one bought half a size up to be safe that causes heel slip through the whole season.
This is the correct method. It takes ten minutes and needs only a piece of paper, a pencil, and a ruler.
Before you start
Measure at the end of the day. Feet swell slightly through the day — the same mechanism that causes adult ankles to be larger in the evening. A foot measured in the morning can be noticeably smaller than the same foot at 4pm. Since your child will be wearing sports shoes through afternoon training and matches, an end-of-day measurement is more representative.
Measure standing up, not sitting. Weight-bearing spreads the foot. A seated measurement will understate the length and width by a small but meaningful amount. Have your child stand normally on the paper with their full weight evenly distributed.
Measure with the socks they'll actually wear. Football socks, shin pads and thin running socks are all different thicknesses, and that difference lands in the measurement.
The method
- Place a piece of plain A4 paper on a hard floor — not carpet, which compresses and introduces error.
- Have your child stand on the paper with their heel against a wall or a straight line drawn at the back of the page.
- Hold a pencil vertically — not at an angle — and trace around the outside of the entire foot. The pencil should be touching the foot, not hovering.
- Mark the longest point of the heel and the longest point of any toe. The big toe is usually longest, but not always — trace carefully at the front.
- Measure heel mark to toe mark in a straight line, in millimetres — that is the number size charts are built on.
- Measure across the widest part of the foot as well. Width is what decides whether a correct length still pinches.
Measure both feet. Most children's feet are slightly different sizes. Always buy for the larger foot.
Reading the measurement
Once you have the length in millimetres, convert to a shoe size. Sports retailers here sell in European (EU) sizing, so the EU number is the one to buy on.
The part that catches people out is that a UK size is not a fixed length. It is a label, and every brand converts it to EU sizing in its own way. Here is the same UK size at three of the biggest, taken from their own published size charts:
| UK | adidas | Nike | Puma |
|---|---|---|---|
| 3 | 35.5 | 35.5 | 35.5 |
| 3.5 | 36 | 36 | 36 |
| 4 | 36⅔ | 36.5 | 37 |
| 4.5 | 37⅓ | 37.5 | 37.5 |
| 5 | 38 | 38 | 38 |
| 5.5 | 38⅔ | 38.5 | 38.5 |
| 6 | 39⅓ | 39 | 39 |
They agree at UK 3, 3.5 and 5. At UK 4 they give three different answers — 36⅔, 36.5 and 37 — which is half a European size of spread on one number.
The reason is arithmetic rather than carelessness. A UK half-size is about 4.2mm of foot; an EU half-size is about 3.3mm. The two scales do not divide into each other, so a brand converting from a UK last has to land somewhere: adidas moves in EU thirds, Nike and Puma round to EU halves. Neither is wrong.
It is wider at the small end. At a kids' UK 7.5, Nike's chart says EU 24 while adidas and On Running both say EU 25 — a full European size between brands on toddler feet, which is where a size error does the most damage because the child cannot tell you.
And within one brand it is not always one number either. Nike's own kids' chart lists UK 6 twice — once as EU 39 and once as EU 40.
So buying the same UK size across brands does not get you the same shoe. Measure the foot in millimetres, buy on the EU number, and check the chart for the brand in front of you.
A reference guide:
| Foot length (mm) | EU size | UK kids' size |
|---|---|---|
| 160 | 25 | 8 |
| 175 | 27–28 | 10 |
| 190 | 30 | 12 |
| 205 | 32 | 1 |
| 220 | 34–35 | 2.5 |
| 235 | 37 | 4 |
| 250 | 39 | 6 |
| 265 | 41 | 7.5 |
This is a general guide to the EU number. For the reason above it can only ever be a guide — always cross-reference against the chart for the brand you are buying, especially for football boots where fit runs different from running shoes.
The thumb-width rule
Once a shoe is on the child's foot, fully laced, standing up: there should be roughly a thumb's width of space between the end of their longest toe and the end of the shoe.
Less than this and the shoe is too small — toes will compress against the end during running and direction changes. More than this and the shoe is too large — the foot will slide forward on impact, causing heel slip and the toe-gripping habit that stresses the small muscles of the foot.
Sports shoes are performance-fit and sit closer than school shoes, which carry a larger allowance because they are worn for long periods at low intensity. So a school-shoe fit will feel about right on a sports shoe and still be too loose for a pitch.
How often to measure
How often a foot needs re-measuring changes with age:
- Under 3 years: every 6–8 weeks
- 3 to 6 years: every 2–3 months
- 6 to 12 years: every 3–4 months
- 12 and over: every 4–6 months, or when they mention discomfort
In Dubai's sports calendar, a practical minimum: measure at the start of each season in September or October, again at the winter break in January, and whenever your child says their shoes feel tight. The foot that fitted in September may not fit in February. Last season's size is not a reliable guide.
When the size is right but the shoe still doesn't fit
Sizing charts are averages. Width variation, brand differences, and individual foot shape mean the correct size on paper can still be wrong in practice.
Watch for:
- Redness or blisters at the toes or heel after the first few wears
- Your child removing the shoes during breaks without being asked
- A visible bulge at the side of the shoe at the widest point of the foot (too narrow)
- Noticeable heel slip when running (shoe too long, or heel cup too wide)
If these appear in the correct size, the problem is width or last shape, not length. Trying a different brand, or going half a size down with a wider fit, often resolves it — and the difference in fit between a narrow-lasted and wide-lasted boot of the same size can be significant.
Brand conversions above are from each brand's own published kids' size chart, read 9 September 2026: adidas UK, Nike UK, Puma (US size-charts page) and On Running's kids size guide.
Sources: Stracker NH et al. (2023) — children's footwear sizing guidelines review · American Academy of Pediatrics guidance on foot growth rates · Mauch M et al. (2008), Gait & Posture — foot morphology in childhood