What this document settles
It fixes the shape and the dimensions of the part of the boot a binding grips: the thickness and the profile of the toe lug, the height and the form of the heel, the surfaces the toe piece presses on, and the tolerances on all of it. It also covers what the boot is tested for as a boot.
Two forms are described, not one. Type A is the adult sole. Type C is the child form, for the small boots that go into junior bindings. They are not the same geometry, and the document treats them as separate.
The second thing the boot carries is its sole length in millimetres, marked on the heel. That figure is one of the inputs to the release-setting procedure, and it is also what a binding’s heel piece is adjusted to. It is not a shoe size, and it is not the Mondopoint size either — a 27.5 Mondopoint boot has a sole length in the region of 305 mm, and the two numbers are printed side by side on the same boot for different purposes.
What it does not promise
It does not promise comfort, warmth or fit. The last width, the liner, the flex and the buckle layout are all outside it.
It does not cover the touring sole, which is rockered, rubberised and built to be walked in. That is a separate document, and the difference is exactly why a touring boot in an alpine binding is not a combination this site will describe as workable.
It does not cover the walk soles that sit between the two. Those are a licensed geometry rather than a standard of their own, and they have their own page here.
It does not mean every binding accepts every compliant sole. A binding declares which sole standards it takes; some take one, some take several, and the listing is where that is stated or missing.
What it is read alongside
The binding requirements on one side, the touring boot sole standard on the other, and the assembly procedure above both — the sole length this document requires to be marked is one of the four inputs that procedure uses.
Where it turns up on this site
Boots and bindings, and through them every ski sold as a package.
This site handles it in one way, consistently. A boot page prints the sole standard the maker declares and the Mondopoint size as published, and prints the sole length in millimetres where the maker gives it. A binding page prints the sole standards that binding states it accepts. Where either is unstated, the page says so — because an unstated sole standard is the single most expensive silence on this shelf.
The questions asked most often
How do I know which sole my boot has?
It is marked on the boot, usually on the heel or the sole itself, together with the sole length in millimetres. A boot that states nothing is a boot to take to a shop before buying bindings for it.
Are adult and child soles interchangeable?
No. The standard describes them as separate forms, and a junior boot in an adult binding — or the reverse — is outside what either was designed for, even when it physically goes in.
My boot has rubber on the sole. Is it still alpine?
Possibly, and possibly not. Rubber pads are fitted to both the walk soles and the touring soles, and the marking rather than the material is what answers it.
Last reviewed 28 September 2026