You have to make sure that your foot fits volume, width and footbed comfortably, but this is how u can check if you are at the right spot with length:
1. Stand at normal posture in your boots, you should feel your big toe just barely touching the end of the boot, or know that you are very very close to it (like 1/8").
2. Now bend your knees as if you are on your board, pressing your shins into the top of the boot.
3. You can observe 2 things here:
a. your heel sinks and locks into the heel of the boot.
b. your toe will pull back, and never touch the front while riding.
*just make sure that your toe in the standing position is BARELY touching, this is important. If its smushed up against the front even a little, or if its like 1/2" or more away from touching, you are in the wrong size/brand/model.
*a professional bootfitter can do alot to help your boots fit better, but starting with the right size is kind of a no-brainer
*I wear 10s in real shoes, 9 in my boots because they fit so well. Sizing down, up to a size and a half is very common, which should make you consider what you were doing sizing up?
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