How to Choose Ski Boots - Fit and Flex

Nowadays you have a litany of resources at your disposal to find and gather information on what to look for when shopping for your next pair of ski boots. Well, allow us to add another resource for you and provide some vital and useful expertise so your next ski boots purchase will be less stressful. After all, you will probably spend more time in the same ski boots than on the same pair of skis if you own multiple pairs of skis.

Table of Contents

How Are Ski Boots Sized?

Ski boot sizing is measured in what is called Mondopoint. Mondopoint is based on the length of your foot in centimeters and can be determined by simply placing your heel against a wall or other vertical surface with your toes pointed up, and then measuring the distance from the wall to the end of your longest toe in centimeters. If you do not have a metric ruler you can simply multiply the length in inches by 2.54 and you will have the centimeter equivalent that will give you your mondopoint or “Mondo” size.

As an additional item of note, some manufacturers elect to make boots with shells and liners that fit the range from whole size to the half size (e.g. 26.0 - 26.5). What this means is that the shell and liner is the same size but the footbed that comes standard with the boot varies in thickness. You may be asking why they would do this. Well in a nutshell it comes down to the cost to make the boot. The shell and liner components are more expensive and the footbeds are not. So this means that they can produce whole and half sizes without incurring the extra expense of a different shell or liner.

Finally, it is important to know that while you can use a conversion sizing chart to translate your street shoe size into the Mondo size you would need, it isn't the best approach and should be done if you don’t have other means of getting your proper size. Because shoe sizing can vary from brand to brand, and because some people will wear shoes that don’t fit perfectly this makes converting your shoe size to Mondo risky. While most can walk in a shoe that isn’t properly fitted, doing the same thing in ski boots is riskier considering how demanding the activity is.

Best Use

Downhill Ski Boots

This is likely to be the category or ski boot that you are will most likely come across, but it is not the only one. Downhill ski boots will work with any standard ski bindings.

Downhill Ski Boots

Freestyle Ski Boots

If you’re a skier who spends the majority, if not all of your time in terrain park or hitting jumps & rails, you will find that Freestyle ski boots are what you’re looking for. Freestyle boots are designed to ski Read more

Freestyle Ski Boots

Side Country Ski Boots

If you’re an advanced level skier or above and you seek more adventurous terrain on a consistent basis, Side Country ski boots will be perfect for you. Side Country boots offer more grip in the sole and a walk/hike switch Read more

Side Country Ski Boots

Alpine Touring Ski Boots

For the most adventurous skiers, Alpine Touring ski boots offer a lightweight design that is easy to hike/climb/skin in. They allow for easy climbing up and down when seeking the most difficult terrain, but it is important to note that Read more

Alpine Touring Ski Boots

Ski Boot Width

Narrow Medium Wide
Widths in this area can range from 95mm-99mm. These are often found in race style boots or high performance boots. They are designed so that trained boot fitters can shape it to match the skier's foot. Widths in this area can range from 100mm-103mm. Medium last boots are usually found in boots for advanced skiers or performance style ski boots. Widths in this area range from 104mm-106mm. If you are a recreational skier in most any skill level this is what you are typically going to come across. The width here is intended to provide comfort so that you can enjoy your day skiing no matter the terrain you ski or the skill level you ski at.

Skill Level


For first timers or skiers who only have skied a few times. These skiers are learning the basics and fundamentals of skiing.


For skiers who have spent a season or so learning and are comfortable with the basics and fundamentals of skiing. They have control over their skis and will sometimes try more challenging terrain. They ski at moderate speeds but remain cautious. As outlined above, beginner level skiers who are slightly heavier in weight may consider boots in this category so that the boot can respond accordingly to the extra power.

Advanced Intermediate

For skiers that have mastered the basics and are showing solid technique in their progression. Skiers here make more aggressive turns on groomed runs and will begin to explore off-trail skiing as their comfort and confidence levels continue to increase. Moderate speed skiing is done with minimal caution unless conditions require it.


For skiers with very solid technique on advanced level terrain. They can handle most every snow condition and can do so with relative ease. They often will ski at higher speeds but may do so with some caution depending on conditions.


For skiers who are capable of skiing in control at high speeds safely regardless of snow conditions. They have strong technique, will ski aggressively, and require a boot that will provide the necessary flex and support for the aggressive style.



Simple and straightforward - men’s ski boots are designed for the shape of the male foot, calf, and leg shape. Typically you will find that ski boots here have a taller cuff compared to women’s specific ski boots, and also have some extra width to accommodate the anatomy of the male foot. Additionally, men’s ski boots are designed with a stiffer flex due to the higher average weight of the male skier and the aggressive nature men tend to ski with.


As is the case with women’s specific skis, women’s ski boots are designed for the female skiers specifically. It doesn’t take a genius to recognize that the average weight of a female skier is less than that of a male skier. Additionally, the shape of a female skier's foot is going to be starkly different, particularly when it comes to width, the leg shape in the cuff region and also where a woman’s center of gravity is positioned in comparison to a male skier. Taking all of these items into consideration, most manufacturers nowadays make women’s specific ski boots that have narrower widths, narrower heel pockets, and cuffs to accommodate the variances in a women’s calf and lower leg. To compensate for the modifications needed in women’s ski boots, heel lifts are often added to keep the skier leaning forward so that they do not lose control over their skis due to the variance in center of gravity.


Boot flex is a topic that was mentioned briefly above in the Gender section of this guide and other areas throughout. Here we will elaborate on this important aspect of ski boots a little more.

Flex of a ski boot is essentially how much pressure is required to bend and move a ski boot. This is represented by a number, typically anywhere from 30-130, with the higher the number equating to a stiffer ski boot. If you are a bigger skier in stature or very strong physically you will likely be more naturally demanding on your skis and boots. This requires a boot that will give you support and control. This can be done by having a ski boot that offers the proper flex and bend. Inversely, lighter and/or shorter skiers will want to consider a slightly lower flex rating that will offer the proper amount of stability and rebound.

It is important to understand that across manufacturers there is not an “industry standard”. So what does this mean? Well, essentially it means that across brands you may find that a 110 flex, for example, doesn’t feel the same. Variations in the materials the boot is made from, the boot design, and the number of buckles can cause one to flex more than another or feel more stiff than another.

So what should you consider when it comes to finding the flex ski boot that is best for you? Our suggestion would be to consider your skiing level (ability), your height, weight, how aggressive you are as a skier, and how much your ankles flex. Based on these considerations you can use the guidelines below to identify where you fall in flex rating:

Flex Men's Rating Women's Rating Ability Level
Soft 50 - 70 40 - 60 Beginner
Medium 70 - 90 40 - 60 Intermediate
Medium / Stiff 80 - 100 70 - 80 Advanced Intermediate
Stiff 90 - 110 80 - 90 Advanced

Kids Ski Boots

Skis for kids are narrow in width with short cuffs and soft flex as most skiers looking for boots in this category are beginners, smaller in size, lighter, or some combination of all three. Kids specific ski boots, like their adult counterparts however, can be found for skill-levels from beginner to advanced skier. Just because the ski boots are for kids doesn’t mean that the advanced level skier is left to rip on ski boots that aren’t equipped to handle it.