The most honest and in-depth reviews of outdoor sports equipment on the planet.

Boot Fitting 101: Sizing

Why Do Ski Boots Suck?

The ski boot is the number one reason that recreational skiers do not become diehard skiers, and the rental boot is the main culprit behind the dwindling number of return participants to our sport.

I constantly hear customers complain about how bad their feet hurt, only to find that they have been traumatized by a cheap rental boot that was improperly sized.

How many times can a person go through the tedium of the rental process—let alone the pain and suffering of skiing a whole day in a pair of boots that have been skied by hundreds of other “skiers”—before they either decide to quit skiing or go buy a pair of boots that actually fit?

But if you decide to purchase a boot rather than give up the sport, you might want to think twice before buying boots at a big-box sporting goods store from some kid who was selling a tennis racket or camping gear ten minutes ago.

Furthermore, I spend a lot of time replacing brand new boots that were bought online because they are too big or the wrong shape, so caveat emptor on that front, too.

A properly fitting boot is a skier’s most important piece of gear, and can make or (more likely) break your vacation, even your season. How, then, does a person go about getting a ski boot that fits? What should the aspiring skier know not just about ski boots, but themselves, to make the process easier?

This guide is going to go through just that. By the time we’re done, you will know some of the fundamentals for getting yourself into a great fitting pair of ski boots.

The Factors

There are a number of factors that will determine how well a boot will fit and perform:

➢        Size (length & width)

➢        Foot shape & shell shape (volume)

➢        Lower leg shape & cuff shape

➢        Flex and Biomechanics

➢        Skier experience & ability

The Fit: Getting the Right Size

When determining your correct size, a measuring tool made specifically for ski boot sizing should be used. If you walk into a shop and tell the boot fitter / salesperson that you are looking for ski boots, and he / she does not ask you to remove your shoes and socks in order to measure your feet, run—don’t walk—out of that place!

There are basically three different sizing schemes used when measuring feet: U.S. size, Euro size and Mondo size.

Mondo size is the current default scheme. This is simply a metric measurement in centimeters of the inside of the boot from heel to toe. A size 27.0, for example, is 27 centimeters long from the heel to the toe inside the boot.

A Dirty Little Secret: The Truth about Half Sizes

There is no such thing as a half size. A 27.0 and 27.5 are the same size shell. (SCARPA’s boots are a little different: they size their shells so that the whole size and the half size smaller are the same. For example: a 26.5 and 27 are the same shell.)

Even those who know the truth about half sizes often assume that the boot liners used in a 27.0 and a 27.5 are different, and some manufactures will try to tell you that their liners are sewn in half sizes. Don’t believe it.

The only difference between the whole and half size is the thickness of the removable insole upon which you are standing.

A thicker insole is used for the whole size (27.0) and a thinner insole for the half size larger (27.5). Why is that, you ask? The injection mold used for making ski boots cost upward of $100,000. There are currently 8-9 shells each in men’s and ladies’ sizes. That’s $800,000 – $900,000 per size run per model. There are usually 7-8 different models of boots in any given brand line up. Since the difference between a whole and half size is 5 millimeters, boot manufacturers regard it as financially infeasible to produce an additional 8 or 9 half size shells.

Shell Sizing

The measuring device that was mentioned above should be used as a guide, not a rule. To confirm that the size of the boot you are trying on is correct, you can do a simple test.

Shell sizing is probably the best way to determine your correct size. Simply pull the liner out of the shell and place your foot in the shell. Move your foot to the front of the boot so that your toes are touching. Bend your knee to see how much room there is behind your heel. An easy way to judge this is to use a 1”, ¾”, and  ½” dowel.

1” / 25.4mm behind the heel would be considered a tourist fit.

This skier only skis on green and blue groomed runs on sunny, warm days at very slow speeds and probably has never felt the edge of the ski. This person is perfectly happy to slide around with no thought for performance.

3/4” / 19.1mm of room behind the heel is for the more avid skier.

This skier has some experience. He or she will ski on most trails, and sometimes the most difficult trails. These skiers are intent on improving, and they probably ski between 10 and 20 days a year.

1/2”  / 12.7mm behind the heel is for the expert skier.

These skiers are aggressive and demand instant reaction from their skis. They ski fast on all terrain, but mainly stay in the very steepest chutes and choked trees their mountain has to offer. The only time you see them on a groomed run is on the way back to the lift, the bar, or back to work.

So, What does a “good” fit actually feel like?

Most new skiers and many experienced skiers don’t know what a “good” fitting boot feels like. Out of the box, a new boot should be suspiciously snug, like a firm hand shake. If you have ever offered your hand upon an introduction only to receive a loose, wet noodle from the other person, well, this is not the type of fit you want from your ski boot.

On the other hand, if you have ever had the misfortune of having your hand crushed by some Neanderthal trying to exert his (or her) masculinity, then you can appreciate why this would not make for a “good” fit either.

“Suspiciously snug” means that there is a a firm, even pressure around the whole foot, from the metatarsals back to the heel, and up the lower leg. Only your toes should be able to move. If the boot feels like a bedroom slipper it is too big! (Have you ever golfed or played tennis or rock climbed in bedroom slippers?)

When you first put the boot on, it should feel short.

The toes will feel a little claustrophobic at first. This is OK.

The biggest mistake a new boot buyer makes is judging the size of the boot before buckling it up and bending the ankle joint by driving the knee forward. This simple act will drive the foot rearward into the heel pocket, thereby giving the toes additional space.

It is my opinion that anyone skiing in their measured size is in a size too big.

This is not to say that everyone should down size their boots, but everyone should at least try on one size smaller to see if this is a viable option for the skiing they intend do.

If you do decide to try on a size smaller boot, leave it on for 10 to 15 minutes, flexing and making skiing movements before you decide that it is not for you. You may be surprised.

That’s all for now.

But be sure to check out our next article, Fit Issues and Myths, where we’ll delve a bit deeper into the boot fitting process.

39 Comments

  1. VoS January 28, 2011 Reply

    I’ve been a professional boot fitter for quite sometime. This is a great primer. The difficulty of the boot fit lay with getting good information like this to the once-or-twice-a-year skier that doesn’t surf the net. Great primer, though.

    http://www.voiceofsteezin.com

  2. Frazer Shand December 13, 2011 Reply

    The Atomic B series are the same as the Scarpa as well. They have a shell size that go across sizes. For instance a 23.5 with be the same shell as a 24.0

  3. lrn2swim September 19, 2012 Reply

    got fitted at my local shop a few years ago. just tested my boots for length by taking out the liner and stepping inside. i have about 2 inches behind my heal. whoops. the weird thing is they feel pretty snug all around when on my feet with the liner, i just have a little heal slip every once in a while. any suggestions besides taking the boots back in and asking WTF?

  4. Aaron October 14, 2014 Reply

    Great primer for those new to skiing. Hopefully other skiing resources pick up on it as I imagine the bulk of Blister’s readership is already in the know.

    Here’s a 201 question: Know of any up to date databases containing data points on various boots’ last, volume, flex, etc?

  5. Blister Member
    Steven M October 17, 2014 Reply

    As a boot fitter myself this is a great intro article that ticks all of the key boxes.

    Also, love how you’ve used the same analogies (e.g. firm hand shake) that I use with my customers!

    • Author
      Charlie October 17, 2014 Reply

      Thank you.

  6. Clarissa October 29, 2014 Reply

    Excellent post! We are linkng to this great article on our website.
    Keep up the good writing.

  7. jim November 18, 2014 Reply

    ? On the liner itself, there are some numbers stamped such as “0151215-18” That is the liners size. So what size is this liner. I deal a lot with kids boots that are used and the shell size is worn off many times. So I pull out the liner to see what size they are.

    • Author
      Charlie December 9, 2014 Reply

      Look for the boot shell length usually stamped on the heel lug of the boot. When all else fails, shell size.

  8. Eric November 20, 2014 Reply

    at the end of last season I got a pair of BD Factor MX and I have been experiencing heel numbness. A bootfitter installed a wedge in the heel and it didn’t seem to do much. Any recommendations?

    Thanks!

    • Author
      Charlie December 9, 2014 Reply

      Heel numbness is typically a pinched nerve. Finding where the nerve is being pinched is not easy. You need to see an experienced boot fitter.

  9. Minh December 11, 2014 Reply

    Hi, the last few seasons my pinky toes on the left foot and on the right foot numb up. Whether I’m in ski boots skiing or in boots snowboarding, it’s always the pinky toes numbing up after about 35 minutes. The rest of my feet and legs feel fine in the boots. Is there a quick remedy for numbing pinky toes, any adjustments I can do to my boots? (Vans Matlock Boa snowboarding boots and Lange Banshee ski boots)

    • Author
      Charlie March 1, 2015 Reply

      Sorry it took so long to respond. I don’t always get notifications of comments.

      Do you have custom foot beds? That would be the first thing to do.

  10. Jenn February 28, 2015 Reply

    Great primer. However, your ski level characterizations are off-the-mark. East coast skiing has few steep chutes and not much powder. We’re skiing icy slopes and groomed runs more often than not. We’re still expert skiers. And it’s probably the reality for far more expert skiers than you think.

    • Author
      Charlie March 1, 2015 Reply

      I’m not exactly sure what you’re commenting on.

  11. Joel February 28, 2015 Reply

    Just bought a set of Dynafit Radicals for touring. Toes seem pretty squished when I’m in walk mode, not buckled. I want to make sure they are going to be comfortable all day. Any comments on length sizing when all day touring comfort is important? Seems like there won’t be as much give in the liner in that direction. Thanks

    • Author
      Charlie March 1, 2015 Reply

      It’s kind of hard to say. Have you tried leaving them buckled? Do you have custom foot beds? How is your ankle joint range of motion?? Is there a knowledgeable boot fitter near you?

  12. Aaron April 12, 2015 Reply

    Boots are the single most important piece of the skiing. With the wrong boots or the wrong size boots, even the best ski won’t turn.

  13. Bill August 5, 2015 Reply

    Curious, the last set of boots I purchased were a set of Heads. We did the half inch measurement and initially the boots felt ok walking around in them in the store for around 15-20 minutes. Unfortunately, I wear a size 13-14 with a size 14 instep. I ended up in a pair of 29.5s because of this 1/2 inch fitting ‘technique’ and they’ve given me nothing but problems including a neuroma, even after multiple trips to a fitter. I read in the advanced primer about volume, but it seems to me that as long as the instep is fit, and that your toes have room, it would be better to go big and have a form that’s actually fit to the foot itself, instead of cramming your foot into something smaller and hoping that you can buckle it down enough that the shell molds to your foot? Am I off in thinking this, as it seems the current recommendations aren’t really to fit the instep? Not trying to be hyper critical here, just curious. Thanks for the information in this one as well as the follow up article.

  14. Louis Rosenfeld November 6, 2015 Reply

    Mostly this is good advice but there are a few corrections necessary. Mondo sizing is not the length of the boot inside in cm. It is the length of your foot in cm. The inside of the boot is nearly one cm longer.

    There should be no difference in fit length between Beginner, Intermediates and Experts. A good fit is a good fit and works for everyone. Downsizing from Mondo is almost certainly too small for most people except in the few boots that run long such as some Rossi, Langes and Dalbellos.

    The characterization of good skiers as not spending any time on groomed is off the mark.

    Definitely the boot even if sized correctly will feel small when you first put your foot in.\

  15. Louis Rosenfeld November 6, 2015 Reply

    Just read the next article Fit Issues and Myths and see the Brannock shown is in U.S. sizing. If measured in U.S. size yes everyone needs to downsize, but if measured in Mondo it shouldn’t be necessary.

    • Charlie November 9, 2015 Reply

      Hi Louis,
      Thank you for the correction on the mondo sizing (in the shell measurement).

      A good fit is a good fit i agree, but that “good fit” will differ from individual to individual. I measure 29.5 and i ski in 27.5. This is a good fit for me, but not for 90% of skiers. I’m down sized by 2 sizes mondo, not American. Some skiers i have down sized one size. Others i have up-sized 3 sizes. It’s all based on the needs of the individual. A good boot fitter has the skills to recognize those needs. As far as what brand of ski boot can or cannot be down sized, that’s irrelevant. It’s really up to the customer to decide. If the customer is never given the choice, then no one will ever know. Each customer MUST be treated as an individual and given all the information the knowledgeable boot fitter has at his/her disposal in order for the customer to make a good decision. If i think a customer will benefit from a smaller boot, i will let them try the smaller boot on as an option and let them decide if it is right for them.

  16. weezul December 29, 2015 Reply

    As a skiier, not a bootfitter, I have a different perspective. Since I don’t race, performance isn’t my number one concern. Lasting through the day without getting cold toes is more important. I’ve had the shell of my downhill boots punched out, and even so, 90% of the time I don’t buckle my foot. This gets me down all the blacks when resort skiing. I’ll only do the buckles if hitting double diamond runs, or want to run some moguls, but then I undo them when I’m through. Snug ankles, roomy toes. That’s what it’s about. Don’t let the retail shops tell you different.

  17. Naha January 6, 2016 Reply

    I went from mondo 27 (my shoe size) to 26 and boy after staying with the boot on for 30 minutes my feet were completely numb. I really tried to stay with the ski boot on for 1 hour but after 45 minutes had to take them off. Length was right but sides were killing. You mentioned firm handshake but this was like someone was squeezing my foot with the door really.
    I went then to 27 which is also my shoe size and the boot fit as a sock in most parts except the toes where i had bit room in front. I personally cannot imagine lasting on the slopes for the whole day if the boots are causing too much pain but that is just me. I think the point you might be missing is that in theory the mondo size takes into consideration not only the length but also the width of the foot. From wiki: “It is based on the mean foot length and width for which the shoe is suitable, measured in millimetres. A shoe size of 280/110 indicates a mean foot length of 280 millimetres (11 in) and width of 110 millimetres (4.3 in).Because Mondopoint also takes the foot width into account, it allows for better fitting than most other systems.” That is the reason why i think most of us should stick with our mondo and not scale down. Unless one has very thin feet :)

  18. Diane Neubauer January 10, 2016 Reply

    Being from Iowa, we only get to ski once a year for 5 – 6 days… I love my Lange 24.5 size boots except for the fact a couple of years in a row my two big toes get bruised going down chutes and through the trees and my toe nails end up turning black and falling off later in the summer… ick. Are they too large/long causing a shift of my foot in the boot or ??? I’m buying new boots this year but not sure what direction to take.

    • Author
      charlie January 13, 2016 Reply

      This is common with many skiers who are in boots too long. The mechanism of injury is typically when the skier is thrown into the back seat usually in tougher terrain. This forces the foot forward slamming the toe into the front of the boot. I think you should at least try on the 23.5 and feel for yourself if it’s right for you. The closer the fit the less likely you will impact the front of the boot.

      • Marc Moseley January 19, 2016 Reply

        I had this happen in boots that are too small. First gen Garmont Radium. My foot measures 26.7 cm , my last Garmont (Mega Rides) were 27.0 so I went with 26.5 in the Radium (next shell size down). That was a mistake. Can’t move my toes, can’t even really get them to flatten out. Thought it was just because I wasn’t leaning aggressively like I ski, but after the first day of touring, my big toe nail went black. Can’t keep the forefoot buckled without significant pain. And while the 26.5 should have fit me in theory, I’ve read over on Wildsnow that the first gen Radiums were abnormally small in toe volume and people often sizing that boot up. Wish I’d know that before I bought them. I’m about to drop some $$ on Scarpa Freedom SLs in 26.5, hope I have better luck.

        • Author
          charlie January 20, 2016 Reply

          The thing about scarpa sizing that most people don’t know is it breaks differently than all other Ski boot companies. With scarpa the 26.5 and 27 are the same size. You’re right about the radium. They were miss-sized. If you measure 26.5/27 the freedom 27 shell will be fine.

  19. You're Not That Fast October 31, 2016 Reply

    remember any good boot fitter can make a boot one size bigger.
    you can never make a bigger boot smaller

  20. Brian November 22, 2016 Reply

    Great information!
    Not everyone can get to a ski shop/fitter to purchase boots, I am in rural SD.
    I have buddies in CO and will be skiing there mostly.
    I am a beginner- intermediate level rec somewhat assertive skier
    Tired of rental boots/skis I am buying my own.

    Question…I am a 28 length (socks off & weighted) and a 28 volume foot
    I can only find the Salomon Xpro 100 boot in 27.5 and 28.5
    Leaning toward the 27.5 due to liking to move/carve but wondering on your thoughts.
    Maybe the 28.5 (US10.5) can be adjusted plenty for a confident fit?
    I wear a 10.5 US in all my shoes
    Thank you for any assistance!
    Brian

    • Author
      Charlie Bradley November 22, 2016 Reply

      Salomon tends to fit big. The xpro is the wider boot. I think the 27.5 would be fine. But if you have a narrow foot the xmax may be a better choice.

  21. Steve K January 15, 2017 Reply

    Great article! But I’m still on the fence with the sizing down idea.

    My foot measures 27.5cm with 99mm last and I tried a pair of 26.5 2013 Lange XT 100’s (last=97mm) with thin ski socks. At first it felt doable; then after 5-10 minutes, pain ensued. I removed the liners and just wore those for about 20-30 minutes. My feet were in pain with just the liners – felt pain and tingling. The toes were pressed and sides squeezed. When I took them off, the outside edges of both feet by the 5th metatarsals were red. I couldn’t imagine putting them on again.

    Would boots like this have been a candidate for a boot fitter to modify or, based on the pain, not so much?
    When you size down, do you size down both the length and last, or just the length?

    Thanks!

    • Author
      Charlie Bradley January 15, 2017 Reply

      As I have stated in the article, down sizing isn’t for everyone. Some can go down two shell sizes and be comfortable, others can go one smaller. But most people can only ski their measured size. It’s up to you and what works for you. A skilled boot fitter can help you make that decision, but in the end, it’s your decision. The decision to down size should NOT be made based upon the boot fitter’s ability to make modifications in order for it to work. If it’s painful, don’t do it.

  22. Scott February 6, 2017 Reply

    I am currently trying on Scarpa Freedom SL 120 boots, which come with Intuition Cross Fit Speed Ride liners. I’m working with two sizes – 29.5 and 30. The shell appears to be the correct fit.

    The 29.5 is tight, but would likely be the right size with one exception – I feel uncomfortable pressure across the top of my instep, even with the buckle as loose as possible. My question is whether the heat molding process can add some space across the top of my instep? Or is it preferable to go with the larger size and attempt to tighten the fit with the liner in the size 30?

    I do have footbeds in the liners. I would prefer to keep the footbeds if I can correct the pressure point from the top of my instep. I will definitely see a boot fitter to have the liners cooked. I live in a state with no boot fitters, so very difficult to try on / size boots. My previous boots were Garmont Endorphines, but are over 10 years old.

    Thanks.

    • Author
      Charlie Bradley February 7, 2017 Reply

      Scarpa shell sizes are different than all other brands where typically the half size shell accommodates the whole size below it ie 29/29.5 is the same shell. With scarpa the 29.5/30 is the same shell. As far as your instep issue, I really couldn’t say without actually measuring. If the pressure is unbearable then I doubt heat molding the liner will be enough to make it comfortable. You might want to try the Lange free tour as an alternative.

  23. Scott February 7, 2017 Reply

    Thanks for the quick feedback. I haven’t tried the Lange, but according to their specs, that looks to be a narrower, lower volume boot than the Scarpa. I’ll keep working on this, but thanks again for the info.

  24. assdksl March 24, 2017 Reply

    Great info, I wish I’ve read it couple of months ago :(
    I bought Dalbello Krypton Fusion’s in 28 size. I’m also measured 28 and fit in the store was… not comfortable. After 10 minutes or so my 5th metatarsal area started hurting. Shell fit on Dalbellos was fine and just for reference, I considered Lange RS110 wide and those were great except too wide in the toe box. I thought that’s because Intuition liner being denser than what I’m used to. Fitter fixed me with custom fotbeds and did liner heat molding too. That seemed to improve heel hold (which was pretty good to start with) and a bit of pain I mentioned. Fitter also said I’ll have slight discomfort first couple of days too until foam completely breaks in. Skied 5 days so far and pain is not gone but decreased and I hope it will disappear completely soon. However, a bit of dead space developed on top of my right foot, mid metatarsal bones to toes. Cant lift heel or instep, its more of a toe scrunch. Side to side I’m still secured. I can get read of it if I tighten that weird reversed front buckle which does not seem to mess with the width but reduces this volume somehow. Maybe it’s something about cabrio boots, don’t know. Feet are measured identical pretty much, shell fit was good according to the boot fitter. Only difference is I probate a bit with right foot which he told me and I’m sure took into account when creating foot beds. My question is, do you still think I should’ve sized down and that boots will brake in and be loose? Also, Is it OK that I use front buckle to get rid of this dead space? I never used to buckle those before and was thought that they are there only to keep snow out, not to alter the fit.

    BR

  25. Yoad Ben-Itzhak October 13, 2017 Reply

    My biggest advice to anyone boot fitting is to try sizing down in length but don’t size down more than 1mm for the last of the boot or vise versa. I used to use the atomic hawx 100 but was losing circulation in my right foot and had to take it off every hour to gain feeling back. I have since switched to an even smaller boot but the fit is so much more comfortable and feels more responsive as well due to the last being almost perfect at 99 while my foot is at 100 on the nose. Great advice for first time buying boots btw, you are clearly very knowledgeable and want to help others!

    • Author
      Charlie Bradley October 13, 2017 Reply

      Thank you. I try to help skiers keep an open mind about sizing. Too many fitters try to railroad customers into what they think is right for the customer without giving options.
      Cheers!

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