How do you choose the right size for ski boots?

Ski boot size is chosen by foot length, not your regular shoe size. You need to measure while wearing the socks you'll actually wear skiing - usually special ski socks, they're thinner than regular ones. The boot should fit snugly but not be tight, so blood circulates normally. If you bought online and picked the wrong size, yeah, your feet will definitely get cold - tight boots mess with blood circulation and your toes freeze way faster. Try putting them on with the right socks and see if they're really squeezing hard.

As for that nut you turn - that's the cuff stiffness adjustment system (if these are alpine skis) or the tightening mechanism (if these are cross-country). You usually turn it to get the boot to fit your foot better, but that won't fix things if the size was wrong to begin with.

If the boots are actually too small, better to exchange them. I'd suggest before your next purchase going to a store where you can try things on and figuring out your exact size. Ski boots are sized in centimeters of foot length, and each manufacturer has their own quirks. Try them on with ski socks and give yourself an extra centimeter of room - feet swell a bit when you're moving.

Yes, you most likely got boots that are a bit too big and are hoping to compensate with thick socks - that's exactly what creates gaps that let cold air through, and your feet end up freezing even more.

That knob is a click system for adjusting the cuff stiffness, it affects how the shaft fits, not the size - try ordering smaller boots and try them on in thin ski socks instead of regular warm ones.

The main rule: a ski boot should fit snugly, but not pinch. If you put it on and feel empty space even with thick socks - that's a sign the size is really too big. Thick socks won't save you; they just create air gaps that let cold seep in. You either need to go down a size or look for special ski socks - they're thin but keep you warm because they're made from moisture-wicking materials.

That knob on the boot - that's the click system for attaching to your skis, not a size adjustment 😊 You turn it so the boot sits properly in the binding. Here's the tricky part: some people think if the boot is too big, they can tighten the straps or velcro and it'll help. It does help, but only if the size difference is really small. If the boot is genuinely a size too large, no amount of tightening will fix it.

I'd recommend trying them on properly: put on ski socks (thin ones, not wool), stand in the boot, and try to wiggle your heel. It shouldn't slide. Your toes should touch the front of the boot, but without sharp pressure. If that's not the case - order a smaller size.