Ski Boot Size Chart and Mondo Conversion (And Why a Chart Can't Fit You)

Ski boots are sized in Mondopoint, which is simply the length of your foot in centimeters. A 26.5 boot fits a 26.5 cm foot. It is not your street shoe size, and converting from your sneakers is the single most common way skiers end up in boots two sizes too big. The chart below converts US, UK and EU sizing to Mondo. Read it, then read the part underneath it, because the chart will get you to the right shelf and it cannot get you to the right boot.

In this article

• Ski boot size chart: Mondo to US, UK and EU
• How to measure your foot for ski boots at home
• Why 26.0 and 26.5 are usually the same boot
• The number the chart leaves out: last width
• What flex number should you be in?
• Why the chart cannot finish the job
• FAQ

Ski boot size chart: Mondo to US, UK and EU

Treat the US, UK and EU columns as a starting point only. Street shoe sizing is not standardized between brands, which is exactly why ski boots abandoned it in favor of Mondopoint, a measurement rather than a label.

How to measure your foot for ski boots at home

You need a wall, a sheet of paper, a pencil and a ruler with centimeters on it.

1. Put on the sock you actually ski in. One thin sock, not two thick ones.
2. Stand on the paper with your heel flat against the wall, weight evenly on both feet.
3. Mark the paper at the tip of your longest toe, which is not always the big toe.
4. Measure from the wall edge of the paper to the mark, in centimeters.
5. Do the other foot. They will differ. Use the longer one.

That number is your Mondo size. A 26.8 cm foot is a 27.0 boot, not a 27.5. Round to the nearest half size and do not add room.

Why 26.0 and 26.5 are usually the same boot

Here is the thing most size charts never tell you. Most alpine boots are built on a shared shell for each full and half size pair. A 26.0 and a 26.5 are typically the identical plastic shell with a slightly different liner thickness. Same for 27.0 and 27.5, and so on up the range.

Two consequences follow. First, if you are between those two sizes, you are not choosing between two boots, you are choosing between two liners in the same boot. Second, the real size jumps happen at the full centimeter, so going from a 26.5 to a 27.0 is a genuine change in shell length while 26.0 to 26.5 largely is not. Skiers who "size up half a size" for comfort often get no extra shell length at all, just a thinner liner that packs out faster and leaves them sloppier by midseason.

The number the chart leaves out: last width

Length is one dimension. The measurement that decides whether a boot is wearable for you is the last, which is the width of the shell at the forefoot, measured in millimeters at the reference size.

Low volume, 98 mm last

Dalbello iL Moro 110 3DWRAP

What a narrow foot should be in. On the shelf in every size from 24.5 to 30.5.

$550 See sizes →

A wide foot in a 98 mm race last will hurt at any length. A narrow foot in a 102 mm shell will swim no matter how correct the Mondo number is. This is the variable that makes two boots of the same stated size fit completely differently, and it is why the chart alone cannot finish the job.

Skip the guessing

Boot Fitting

We measure length, width, instep and stance, then shell fit you in person. In Boulder.

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What flex number should you be in?

Flex is the resistance of the boot when you drive your shin forward. It is not standardized between brands, so a 100 flex in one brand can feel like a 110 in another, but the ranges below hold as a starting point for adult alpine boots.

Body weight matters more than ego here. A stiff boot you cannot flex in the cold keeps you standing upright on your heels, which is the opposite of what a stiff boot is for.

Medium volume, 100 flex

Atomic Hawx Prime R100 BOA

A 100 mm last with BOA closure across the forefoot. The middle of the bell curve, and we stock it deep.

$520 See sizes →

Why the chart cannot finish the job

A size chart knows one number about you. A shell fit knows six. Pull the liner out of the boot, slide your foot forward until your toes touch the front of the shell, and look at the gap behind your heel. One to two fingers is the working range. Three fingers means the boot is too big, whatever the chart said and however good it felt on the carpet.

The chart gets you to a shelf with maybe four candidate boots on it. Last width, instep volume, heel shape and flex decide which one of those four is actually yours. That part takes a person, a shell and about an hour.

Frequently asked questions

What is the US size for a 26.5 ski boot?

A 26.5 Mondo is roughly a US men's 8.5 or a US women's 9.5. Use it as a starting point, then measure your foot in centimeters, because street sizing varies between brands and Mondo does not.

Is ski boot size the same as shoe size?

No. Ski boots use Mondopoint, the length of your foot in centimeters. Street shoes are sold with growing room built in. Converting from your sneakers is how skiers end up one to two sizes too large.

What is a size 7 in a ski boot?

A US men's 7 is about a 25.0 Mondo. A US women's 7 is about a 24.0 Mondo. The men's and women's columns differ by a full size, so make sure you are reading the right one.

Should ski boots be the same size as your shoes?

No, and they will usually feel a size or more smaller. A correctly sized ski boot has your toes brushing the front of the liner when you stand upright, pulling back slightly when you flex forward into a skiing stance.

How do I know if my ski boots are too big?

Your heel lifts when you flex, you buckle to the tightest notch to feel secure, your toes never touch the front, or you can fit three fingers behind your heel in a shell fit. Any one of those means too big.

Do ski boots stretch out over time?

The shell does not, but the liner packs out, typically losing a noticeable amount of volume in the first 15 to 20 days of skiing. Buy the fit you want in February, not the one that feels pleasant in October.

Related reading: How Much Does Ski Boot Fitting Cost? and Why a Proper Boot Fit Matters More Than Your Skis.