How To Properly Fit Your Ski Boots At Home

When the weather starts cooling down and skiers start thinking about gearing up for winter, many of us start checking out that sexy new pair of rockered skis that will transform those upcoming powder days into something truly epic. Unfortunately, many skiers think about their ski boots last—the process is pricey, it takes time to get right, and the myriad of choices available now can be overwhelming.

In a perfect world, we’d all be thinking about our boots first and foremost. They are our most important connection to the snow, and a perfectly-dialed boot can make the difference between feeling like a Formula 1 driver on the slopes, or having a miserable day full of pain, shin bang and wasted effort getting your skis on edge. If you’ve never skied in a boot where your heels and ankles feel locked in and comfortable—you're missing out on skiing and feeling your best.

If you’re lucky enough to be in a location where you have access to a great bootfitter, get in there! These foot scientists will help you not only choose the right shell for those uniquely-shaped flippers of yours, but they typically will include any work like molding liners and tweaking your shell in the price of the boot.

That said, we know not everyone has access to a great local shop, and of course not all shops are created equal. This guide is not intended to replace a trip to a boot fitter, but it can hopefully help those of us who might need to pull the trigger on some boots before they can make a trip to a place with the right local options to get them dialed in.

I called up one of my favorite local shops, Salt Lake City’s Lift House, and spoke to bootfitter Luke Larsen to get some insider knowledge for those of us trying to narrow down our options.

Use the Two-Finger Test to Measure Length

The first step any fitter will take is to try to dial in sizing. Luke says 99 percent of the time he finds customers can drop one to two full sizes from their street shoe to the corresponding mondopoint size. For reference, mondopoint size is a measurement of the length of your foot in centimeters, and roughly corresponds to how long the inside of the boot is.

Ski boots are meant to fit differently than street shoes so don’t try to size them the same way, even if you’re spending all your time in the park! Just because your pants are loose doesn't mean your boots should be! Keep in mind that the liner foam will pack out over time, and a little extra snugness will likely not be an issue after you spend some time skiing.

The two-finger test is the next step, and the best way to double check you have the correct size once you have your new boot in hand. Pull out the liner of the boot and slide your foot in until your toes barely touch the front of the shell. Now slide two stacked fingers behind your heel [illustration/image here?]. For a performance fit, your two fingers should feel snug between your heel and the shell–for the most precise fit possible, especially if you know you can get some molding or grinding work done from a bootfitter, take it down to 1-1.5 fingers.

Measure the Width

Bootfitting is sometimes more art than science, and this is where things can get complicated. Fitters will start off with a width measurement in millimeters–you can use a printable brannock device like this one to get a close idea of whether your foot falls into the wide or narrow category.

Related: Buying Ski Boots Online: The Ultimate Walkthrough

Luke mentions an important note–the “last width” spec you see as part of a boot’s specs online is standardized ONLY for a size 26.5 shell. You can count on an increase or decrease of 2-3mm for every size you go up or down, so measure your width accordingly.

For most of us that want a performance fit, a “narrow” or 97-99mm last will be the ticket. You would then jump up to last widths of 100-102mm, followed by wide-lasted boots in the 102-106mm range. Worth mentioning are the many new BOA options which allow you to literally dial in your last width within about a 2-4mm range.

Double-Check Your Ski Boot Volume

Many manufacturers are offering the same model boot in multiple volume options. Typically, you will find wider lasts in medium to high volume boots, and once again you can count on the last changing off of the stated 26.5 size. For most of us that want a performance fit, a “narrow” or 97-99mm last will be the ticket. Higher volume also will correspond to more room vertically for your instep (typically the tallest part of your foot in front of your arch).

There’s a few ways to deal with instep issues. Remember this part of your foot is highly sensitive. I’ve found that too often, a huge factor for instep issues is over-buckling your front buckles. There should be just enough pressure on your front buckle (in a three-buckle boot) or your front two buckles (in a traditional wrap/four-buckle boot) to keep snow out. Any more pressure is not really doing much to lock your foot down as the more rearward buckles will do that work for you.

Related: Choosing A Backcountry Freeride Boot

In short, use a combination of your brannock measurement, last width, shell fit and instep height to determine if you need to make that important decision to step up in volume. If you are on the fence or have any doubt here, you’ll want to figure out a way to get to that bootfitter.

A Note on Ski Touring Boots

This fit guide is geared towards alpine/resort-only boots, but the same general rules hold true for ski touring boots. There's long been a rule of thumb to size up your ski touring boots to allow room for your feet to swell, and give yourself some more toe room while your hike our ski tour. These days, modern ski touring boots meant to fit and ski similarly to an alpine boot, and have shells already designed to accommodate your foot moving differently while your walk uphill. In fact, many boots, like the Tecnica Zero G Tour Pro, have long internal shell lengths for their corresponding mondopoint size to give you more toe room right out of the box.

That being said, when using the two-finger test to test for shell length, aim towards the looser end of the spectrum. Instep volume and width should still be fit the same as in an alpine boot. With too loose of a touring boot, you'll get blisters right away.

The Bottom Line

What we’ve covered here should hopefully be enough to avoid the major pitfalls of buying your boots online, but it’s by no means a comprehensive list of factors. Other tweaks to liners, buckles, canting and more should be done by someone qualified so that you don't make a problem worse or create a new one.

And if you do purchase online, I personally can’t recommend custom footbeds in your boots enough. Even if you don’t do it right away it’s something you should highly consider adding on later in the season, or before the next big trip. If you’ve been skiing a long time without them and are just getting on board, they will change your skiing overnight! While custom footbeds are the gold standard here, there are plenty of decent off-the-shelf options that are far less expensive, but won’t give you the full-custom treatment.

If you find yourself in the SLC area, make sure to visit Luke and some of the other awesome fitters at the Lift House at the base of Big Cottonwood Canyon!