A junior ski boot’s mondopoint size is not a conversion of anything. It is your child’s foot length in centimetres. A mondo 22.5 boot is built for a 22.5 cm foot, and that is true in every brand — it is the one number in children’s sizing that means the same thing everywhere.
The unreliable number is the US shoe size printed beside it. Four published junior charts put a US youth 1 anywhere from a mondo 19 to a mondo 20.5 — a centimetre and a half of boot length, on a fit whose entire working tolerance is about two centimetres. So measure the foot and buy that number. Do not convert from a sneaker.
Youth ski boot size chart
Measure the child’s bare foot in centimetres. That measurement is the mondopoint size. There is no table to look anything up in — the conversion below exists only because most American parents own an imperial tape measure.
| Foot length | In inches | Mondopoint (boot size) |
|---|---|---|
| 17.5 cm | 6.9″ | 17.5 |
| 18.5 cm | 7.3″ | 18.5 |
| 19.5 cm | 7.7″ | 19.5 |
| 20.5 cm | 8.1″ | 20.5 |
| 21.5 cm | 8.5″ | 21.5 |
| 22.5 cm | 8.9″ | 22.5 |
| 23.5 cm | 9.3″ | 23.5 |
| 24.5 cm | 9.6″ | 24.5 |
| 25.5 cm | 10.0″ | 25.5 |
| 26.5 cm | 10.4″ | 26.5 |
Inches are our own arithmetic at 2.54 cm to the inch, rounded to a tenth. The junior mondopoint range runs from about 14 to 28 across the brands; most junior catalogues start around 17.5. Which half-sizes actually exist depends on the model — one manufacturer’s junior chart steps in half centimetres while another lists its junior model a full centimetre apart.
Four published charts, four different answers
Here is what happens if you start from the shoe size instead. Each column is one published junior chart, read from a US youth size across to the mondopoint it recommends:
| US youth size | Nordica (copy A) | Nordica (copy B) | Dalbello | Head | Spread |
|---|---|---|---|---|---|
| 1 | 19 | 20.5 | 20.5 | 20 | 1.5 cm |
| 2 | 20 | 21 | — | 21 | 1 cm |
| 3 | 21 | 21.5 | — | 22 | 1 cm |
| 4 | 22 | 22 | — | 22.5 | 0.5 cm |
| 5 | 23 | 23 | 23.5 | 23.5 | 0.5 cm |
| 6 | 24 | 24 | — | 24.5 | 0.5 cm |
Dashes are sizes a chart does not publish a row for. The pattern is the one that matters: the disagreement is worst in the smallest boots and shrinks as the foot grows. At a US youth 1 the four charts span a centimetre and a half. By a US youth 5 they are within half a centimetre of each other.
Two copies of one brand’s chart disagree with each other
Columns A and B above are both presented as Nordica’s junior chart, by two different retailers. They agree exactly from mondo 22.5 upward and diverge below it — copy A puts a US youth 1 at mondo 19, copy B at 20.5.
We could not settle which transcription is faithful, and we want to be straight about why. We downloaded Nordica’s own sizing PDF, and the chart in it is published as an image rather than as text, so there is nothing in the file to re-key against. One of the two copies is a transcription error and we cannot tell you which. What we can tell you is the conclusion, which does not depend on resolving it: if two reprints of a single manufacturer’s junior chart can disagree by a centimetre and a half, the shoe-size column is not a measurement. Measure the foot.
Readers of our other size guides will recognise the shape of this. The same thing happens with youth t-shirts, where two copies of one maker’s spec sheet publish identical inches against different numeric sizes, and with youth shoes, where a manufacturer’s own centimetre column disagrees with the one its retailers print. It is not a coincidence in any of the three cases. Letters and numbers on children’s sizing are conventions that get copied; measurements are not.
Do not size up a ski boot for growth
This is the one place where the standard children’s footwear advice is actively wrong. With sneakers you leave about half an inch of growing room. With a ski boot you buy the length that fits now, because a foot that slides around inside the shell cannot steer the ski. The boot is a steering control, not a shoe.
The check a bootfitter uses is the shell fit: the liner comes out, the child stands in the bare shell in a ski sock, slides the foot forward until the toes touch the front, and the fitter looks at the gap behind the heel. Published guidance puts that gap at roughly 15 to 20 millimetres, and tighter for stronger skiers. Hold that number next to the table above — the disagreement between four shoe-size charts at a US youth 1 is 15 mm, which is the entire correct gap. That is the whole reason this page leads with a tape measure.
If the cost of replacing outgrown boots is the real problem, the answer is a seasonal lease or a shop’s trade-in programme, not a boot bought two sizes long.
Three numbers that are not the same number
- Foot length — what you measure, in centimetres or millimetres.
- Mondopoint — the size on the boot, meant to match that foot length.
- Boot sole length (BSL) — the length of the boot’s outer sole in millimetres, stamped on the heel of the shell. This is the number bindings are set from, and it is much larger than the foot; the shell is longer than what is inside it. A 26.5 boot does not have a 265 mm sole.
Do not calculate binding settings from a chart at home. Read the BSL off the heel and have the bindings set by a shop.
Junior flex ratings
Flex is the second number on a junior boot, and unlike mondopoint it is not standardised between brands — a 70 in one line is not a 70 in another. Within a single brand it is still a useful guide. Nordica publishes these bands for its junior boots:
| Flex | Nordica’s description | Who it is for |
|---|---|---|
| 50–25 | soft | young skiers, first-time skiing |
| 70–60 | medium | young intermediate skiers |
| 90 | hard | young, more expert skiers |
A child in a boot that is too stiff cannot bend it to turn, which looks exactly like a child who cannot ski. Softer is the safer error here, and most kids who ski a handful of days a season belong in the bottom band.
Width is the other half of the fit
Length gets all the attention and width causes as many bad days. Boot width is described as the “last” in millimetres across the forefoot — the same manufacturer describes 98 mm as narrow or close-fitting, 100 mm as medium, and 102 mm as wide or comfort-oriented, in its adult range. A boot that is too wide feels loose in almost exactly the way a boot that is too long feels loose, and the two get confused constantly. If the length is right on the tape and the boot still swims, suspect width.
How to measure for a ski boot
- Bare foot, no sock. Ski-boot sizing is to the foot itself, not the foot in a shoe — which is why a mondo 22.5 boot feels far shorter than a 22.5 cm sneaker.
- Stand on paper with the heel against a wall and the weight on the foot.
- Mark the end of the longest toe. Measure from the wall to the mark in centimetres.
- Do both feet. Use the longer one. That number is the mondopoint size.
Measure again before every season. Feet grow in bursts and a boot that fit in March can be a size short by December.
Why there are no product links on this page
We link to products on most of our guides and we are deliberately not doing it here. A junior ski boot is the one piece of kids’ equipment where the fit is decided with the foot in the bare shell, and we would be sending you to buy a boot no one has checked. Measure at home so you know which rows of the chart you are in, then have the shell chosen on the child’s foot — at a shop, a rental counter or a seasonal lease programme.
Sources and verification
The mondopoint definition and the shell-check figures are consistent across every source we read. The conversion tables are not, and that disagreement is the subject of this page rather than something we resolved:
- Nordica, copy A — the junior chart as transcribed and dated by a specialist bootfitting retailer, which links the manufacturer’s original PDF.
- Nordica, copy B — the junior chart as published by a second retailer. It disagrees with copy A below mondo 22.5.
- Nordica’s own PDF — downloaded and checked. The size chart is an embedded image, so it cannot be re-keyed from the file; the junior flex bands above are read directly from the document’s text and are the manufacturer’s own wording.
- Dalbello and Head — junior charts as published in a retailer’s brand-by-brand size guides.
- Two further general ski-boot charts were checked against these and fall inside the same spread; they are not reproduced above because adding more copies of a disputed conversion does not make it less disputed.
We are not a bootfitting shop and these are published figures, compared. Manufacturers revise charts without notice.
Last verified: 28 September 2026. Spotted a number that has changed? Tell us — corrections get the chart re-checked and re-dated.
Skis are sized separately, by the child’s height and weight rather than by foot: see our kids ski size chart. More charts: every kids size chart in one place.
