Ski boot size chart, and how to measure your foot at home

The chart

Measuring, with a piece of paper

1. Put a sheet of paper on a hard floor with one edge against a wall. Carpet gives a wrong reading because the heel sinks into it.
2. Stand on the paper with your heel against the wall, in the thin ski sock you will actually wear. Standing matters: a foot lengthens and spreads under body weight, and measuring sitting down gets you a boot that is too short.
3. Mark the paper at the end of your longest toe, which is not always the big toe.
4. Measure wall edge to mark in millimeters. Do both feet and use the larger one.
5. Divide by ten. That is your starting Mondopoint size.

Do this before you go to a rental counter as well as before you buy. It turns the first morning of a trip from a guess into a transaction.

Why half sizes often are not half sizes

Most ski boot brands build one shell for two consecutive Mondopoint sizes and change only the liner thickness between them. So a 26.5 and a 27.0 are frequently the same plastic shell with different liners.

This matters when you are between sizes: the smaller of the pair has a thicker liner that will pack down with use, so it is usually the better choice for someone who wants a precise fit. It is also why a boot fitter talks about shells rather than sizes.

The shell fit check, which a fitter will do

This is the check that tells you whether a boot is genuinely your size, and it is worth knowing about even if you never do it yourself.

1. Take the liner out of the boot entirely.
2. Put your bare foot into the empty plastic shell.
3. Slide your foot forward until your toes touch the front.
4. Have someone measure the gap behind your heel. Roughly one to two fingers is a normal recreational fit. Less than one finger is a performance fit and will hurt a beginner. More than two fingers means the shell is too big, whatever the number on the outside says.

Boot flex, the other number

Adult ski boots carry a flex number, usually somewhere between 60 and 130. It describes how hard the boot is to bend forward. Higher is stiffer.

• 60 to 80: soft. Correct for beginners and lighter skiers, because a boot you cannot bend gives you no feedback.
• 80 to 100: the general recreational range.
• 100 and up: stiff, for strong or fast skiers. Actively unhelpful for a beginner.

Flex numbers are not standardized between brands, so an 80 from one maker is not exactly an 80 from another. Treat it as a rough band rather than a specification.

The honest recommendation

Rent, unless you ski enough days that the fee and the queue annoy you. Boots are the item where fit matters most and can only be judged with your foot inside the shell, and a rental counter will swap a boot that hurts. The full case is here.

And when you do rent, wear one thin sock rather than a thick one. It is the single most common way people make a correctly sized rental boot feel wrong. Why thin socks are warmer in a ski boot.

Children

Same system, smaller numbers, and a much tighter growth allowance. The children’s boot chart is here, including why half a size is all the room you get and why a seasonal lease usually beats buying.