1: Place your foot on top of a blank paper and against the wall (and don’t forget to wear socks).
2: Use a pencil (don't forget to have it straight as it shows on Step 2) to mark the longest toe of your foot. We advise you to repeat the same process for the other foot.
3: Use a ruler to measure the length between the longest toe of your foot and the wall.
Based on this measure, you can chose your number.
Scroll down and check the guide for your model.