Whether you are buying your first pair of ski boots, upgrading to a more advanced model or getting into ski racing, the ski boot you choose will have a dramatic impact on your performance and skiing enjoyment. In considering your options it is important to realize that performance and comfort often work conversely in the ridged environment of an off-the-shelf ski boot. The goal is to find a balance between a snug fit (performance) and relaxed fit (comfort). Here are some guidelines that are important to consider at any skill level.
Determining Your Size
Go to the our easy-to-use sizing/conversion charts for any brand boot. Note your shoe size on the chart and determine the equivalent boot size. In doing so you can cross-reference either the US sizing or the Mondo (International sizing) standard as it applies to each brand. If you are unsure of your size, simply print out the International Sizing Chart (from the PDF sizing file provided) and follow the sizing chart instructions. Be sure to measure your foot while wearing a thin liner sock as you consult the sizing/comparison chart in a standing even-weighted position.
If you fall between half and whole sizes, there's one important piece of information you need to consider. All ski boot shells change size only in whole sizes. Half sizes are accommodated by adjusting the thickness of the boot liner and/or insole; not by changing the shell size. For the optimum performance/balanced fit, always select the whole size (i.e. 7 vs. 7.5 or 24.0 vs. 24.5). Think twice about downsizing to the next smaller shell. The ski boot is a ridged environment that can be adjusted and customized, but there are general limits to a half size of stretchability for a too restrictive/uncomfortable boot selection. With that in mind, consider that a customized footbed can greatly enhance the fit of the boot you select. Footbeds add support, give more effective toe room, snug up width, and tighten up foot steering performance.
As a rule if you're a beginner to intermediate skier you will want to match your normal shoe size to the equivalent size on the chart and select the full-size shell. If you're an advanced or expert skier you probably already know that a snugger fit affects performance. Buying a boot one size smaller than your measurement is one way of increasing sensitivity to the skis and enhancing performance. Think carefully before you make this buy. If you're intending to downsize, you should be prepared to customize your boots as needed to balance fit with comfort.
When you try on your ski boots wear a thin to mid-weight liner sock—one pair only. The padding of the inside liner of your ski boot is an open-celled foam that is designed to compress and stretch to some degree to fit your feet. Expect your boots to loosen up a bit through use. Wear your boots around the house for a couple of hours intermittently to pre-adjust them before your first ski trip. Note that your boots will fit best when flexed ... snug and comfortable in the heel through forefoot with a little wiggle room for just your toes. When you stand up with your knees straight your toes will just brush the front of the boot liner.
If you are a beginner to intermediate skier consider unbuckling your boots after the first run or two while riding the lift to get some relief from the boots ‘grip' as they continue to break in. If you're an advance to expert skier you know that it can take three to four days before your boots complete their break-in process. Be prepared with alternative socks of varying weights in order to adjust for subtle boots changes. Keep in mind that fit and comfort starts next to the foot and moves out through the liner and shell from there. A comfortable sock makes a world of difference in fit and comfort. A common choice for all skill levels is to combine a light liner sock with a ski boot specific light to medium-weight merino wool.
Beginner boots will be cushier, softer, and become a bit roomier through use than an expert model. The fit will be somewhat tight, which is what you want— a solid, firm, confident connection. Remember these are ski boots not shoes. They are made to perform in a specific manner and that means that they will feel somewhat awkward and often uncomfortable to walk in. When you choose too much comfort, you usually give up boot control, which in turn will inhibit your learning. Typically, when your boots are too big, your toes automatically curl as a way of trying to get a grip on the boot.
A beginner to intermediate skier's boots also will be softer in how they bend/flex, allowing you more flexibility in the knees and ankles. By bending at your knees and ankle, you should be able to place your knees above your toes with moderate effort.
If you are an advanced to expert skier you recognize that you need increased shell support to match your more demanding and responsive skill. Your boots will be very snug but still comfortable throughout your heel, ankle, and forefoot areas. If you haven't bought a new boot in the last 5 years, however, you'll discover that manufacturing technology has improved performance through variable flex profiles. Boots at this level have become a lot softer in forward flex while remaining ridged and responsive laterally and backwards. These softer boots have become easier on your shins, allow more touch and feel through ankle flex while maintaining extreme edge to edge control
If you are buying boots for a child whose feet are still growing, resist the temptation to buy "boots to grow into." It is reasonable to "buy up" one boot size for growth, but don't be tempted to go beyond one size up. Remember the boot has a huge impact on skier fun, comfort, and effort.