Ski Boots Size Chart

To be able to ski on groomed slopes and in powder without worrying about your feet, the choice of ski boots is a critical one. Your boots form an essential partnership with your skis, they must be comfortable and give you sufficient support. Here is our advice to help you make the right choice.

Ski boot features

To find the right model of boots for your needs, you will need to take into account factors such as size, flex, the shape of the boots’ shell and cuff as well as other features like whether there is a walk position.

Men's and women's boots

Men's and women's ski boots are ergonomically adapted to differences in body shape, especially on the calf. Women’s calves are generally lower down the leg than men’s.

The cuff (the high part of the boot) on women's ski boots is therefore lower and flares out towards the top, with a specific shape at the back of the boot to suit calf shape.

Women tend to be more sensitive to the cold and therefore are more prone to problems with blood circulation and venous return, this is why boot liners on women’s lines are generally warmer.


Another important factor to consider when choosing your ski boots is the flex or rigidity of your boot. Flex index is measured on a scale of 60 to 150.  The choice of flex in a ski boot is linked to the skier’s ability and body shape. The higher the skier’s level, the more rigid the boot should be to allow for more efficient power transmission from the legs to the skis. Skiers of a bigger build will also need a stiffer flex.

  • Beginner level: flex index between 60 and 90 for men and between 60 and 70 for women
  • Intermediate level: flex between 90 and 110 for men and between 70 and 90 for women
  • Advanced level: flex index of 110 and over for men and 90 and over for women
  • High level competitors: the stiffest ski boots are reserved for them and have a flex of between 140 and 150.

Flex index isn't an official standard, so differences in rigidity are found between different brands.

You can adjust the rigidity of your ski boots by loosening the top strap if you want them to be more flexible.

Choose the right size


Ski boot sizing uses mondo sizing which is measured in centimeters and corresponds exactly to the longest part of your foot. Unlike normal shoes, ski boots need to fit the skier's foot exactly.  It is estimated that 75% of skiers choose boots that are two sizes too big!

How do you measure the size of your feet and find your mondo size? It's very simple:

  • put a piece of paper against the wall
  • put your foot on this piece of paper with your heel against the wall
  • flex slightly at the knee and draw round the front of your foot
  • do the same with the other foot
  • take the longest measurement, this is your mondo size

Ski boots are generally available in half sizes. If your foot measurement falls between two sizes, anticipate the compression of the boot liner and choose half a size smaller.


The width of a ski boot is referred to as the 'LAST' (measured across the ball of your foot) which is also the widest part of your foot. You can easily find this measurement by drawing around your foot.

You should choose your ski boot width/last by taking into account the level of precision you need when skiing:

  • 92mm: very narrow. For competitors only.
  • 96-98mm: narrow. For a narrow foot or a skier looking for precision rather than comfort.
  • 100mm: average. Suited to most skiers
  • 102mm: for wide feet.
  • 104mm: for very wide feet.

Choose a boot that is the right width for you, is comfortable and also gives you control of your skis. If precision is important to you, choose narrower ski boots. Ski boots that are too wide won't support your foot and controlling your skis will be more difficult.

Define your type of skiing

Choosing a boot adapted to your foot (men / women, size, width) is the first essential stage in your quest for the ideal pair of ski boots.  You also need to choose a range of boots adapted to your type of skiing as boot requirements won't be the same for people with different ski levels or those skiing on different terrains.

Skiing for leisure on groomed slopes

The ski boot models on offer for on-piste skiing are flexible (flex less than 90), comfortable, and easy to use (easy to step into, lightweight, sometimes come with a walk mode).

These boots are suitable if you are beginner or only ski occasionally.

Performance skiing and racing on groomed slopes

If you ski on-piste and at a high level, you should consider a range of boots that are more rigid (flex between 90 and 130 for men and between 70 and 110 for women). These boots will give you more control due to a narrower fit and a high cuff which is inclined towards your toes.


Freeride and freetouring

If you mainly ride off the groomed slopes and have a good technical level, choose freeride boots with rigid flex (around 100 – 120), a straight cuff, and an average boot width of 100mm. There are specific freeride options to make walking easier, such as rubber soles or a walk mode that frees the cuff.

Skiers that freetour use skins to skin up short climbs before skiing down. These skiers should look for lightweight boots for climbing that also perform well in the descents. Boots with inserts make them compatible with touring pin bindings or hybrid bindings specifically made for freetouring.

Ski touring

In ski touring, climbing is done with the help of skins that are fixed underneath the skis and free-heel bindings that make it easier to walk.

Touring boots are light and their walk mode is very efficient in allowing the cuff to move freely. They are very flexible so details of flex aren't shown when buying them.  

The use of metallic inserts is becoming widespread on these boots and it is essential for these inserts to be compatible with light touring pin bindings.


The first thing that freestyle skiers look for is a flexible boot with cushioning in the heel which makes landing jumps more comfortable. The average width at the ball of your foot should be 100mm, allowing for a good compromise between comfort and precision.


Telemark boots and bindings are specific to the sport, due to genuflection, the technique used in turns (the outside ski is in front and the inside leg is bent with the heel lifted up). Telemark boots are chosen half a size to a size bigger than alpine ski boots due to significant flexion.

So, finally you've found the right ski boots but you want to make them more comfortable? Make sure you have the right ski socks. A thermoformable boot liner will adapt to the shape of your foot when heated (best done in a specialist store) and you can also replace the original inner sole with a custom fitted sole fitted to your feet.

Lastly, consider using a boot fitting service offered by specialist stores or podiatrists. This will allow you to custom fit your ski boots by making the shell bigger around pressure points that cause you discomfort.

If your boots are comfortable, you'll be able to put the right foot forward when choosing your skis!

September 10, 2021 — Carlos Strachan