Skiing guide
Kids Ski Boot Size Chart
How to size youth ski boots using Mondopoint — foot length in centimeters, flex ratings explained, and fit checks before heading to the mountain.
Best next step
Check the table, then confirm the brand chart.
Photo: Jochen van Wylick / Unsplash
Ski boots are sized in Mondopoint, which is the foot's length in centimeters. A child with a 22 cm foot wears a size 22 boot. This system eliminates the confusion between US, EU, and UK sizes, but it surprises parents who expect a shoe size. Always measure the foot in centimeters — do not convert from US shoe size, because the rounding introduces error.
Youth ski boots also have a flex rating, which indicates how stiff the boot is. Lower flex numbers are softer and easier to move in — appropriate for beginners and lighter children. A boot that is too stiff prevents forward flex and makes learning harder. Most beginner youth boots run a flex of 50-70. Rental boots are usually pre-set to an appropriate flex for the size, but when buying, ask about the flex number.
Editorial note
We use these guides as starting ranges, then compare the recommendation against brand charts, fit checks, and sport-specific safety rules before surfacing gear links. Read more about how our sizing works.
Spot a range that looks off, or a league rule we should mention? Tell us — corrections make these guides better for every parent.
Step 1
Find the likely size range
| Player / measurement | Starting size | Notes |
|---|---|---|
| Foot length 16-18 cm (approx. US child 9-11) | Mondo 16-18 | Smallest youth range. Check rental stock before visiting the mountain. |
| Foot length 19-21 cm (approx. US child 12-3) | Mondo 19-21 | Common beginner youth range. Flex 50 or lower is appropriate. |
| Foot length 22-24 cm (approx. US youth 4-6) | Mondo 22-24 | Wide range in this zone — some kids move to junior boot at 23+. |
| Foot length 25-27 cm (approx. US youth 7-9) | Mondo 25-27 | Junior to adult crossover. Check width and instep height as well. |
Step 2
Measure before you shop
Points to measure
Ski boot measuring path
Ski boots use Mondopoint sizing (foot length in cm). Measure bare foot on paper.
- 1Foot length (cm)Stand on paper, mark heel and longest toe, measure in cm.
- 2Mondo sizeMondo size equals foot length in cm — this is the boot size.
- 3Flex testBoot should flex forward without the heel lifting.
- 1Have the child stand barefoot on a piece of paper. Trace the outline. Mark the heel and the tip of the longest toe.
- 2Measure the distance from heel to toe mark in centimeters. This is the Mondo size.
- 3Try the boot on with ski socks (thin, not thick athletic socks). The heel should not lift when flexing forward.
Good reasons
When to size up
- Your child is between sizes and the larger size still feels controlled.
- The season is several months long and the gear is not protective headgear.
- The brand chart says the current measurement is at the top of a range.
Avoid these
Common mistakes
- Buying only for growth and making the gear hard to control.
- Skipping the brand chart because another brand fit last season.
- Ignoring league rules for bats, balls, sticks, and protective equipment.
Parent tip
Measure the foot at the end of the day when it is at its largest. Write down the measurement in centimeters — this is the Mondo size you need.
FAQ
Is this size guaranteed to fit?
No. Treat it as a good starting point, then check the brand's official size chart before buying.
What should I do when my child is between sizes?
Consider comfort, growth, position, league rules, and whether the gear is protective. Avoid sizing up helmets without a proper chart match.
Related guides
Know your child's starting size before you shop.
Answer 4 quick questions — sport, gear type, age, and height — and get a beginner-safe size range plus what to avoid.