Altra Rivera 4 Blue

Choose by centimeters (CM)
If you are purchasing this model for the first time, we suggest you choose the size based on the length of your foot in centimeters. Then add a centimeter to the result and convert using the table above. Select the size keeping in mind that your toes need room since your feet, due to the increased circulation, tend to swell while running and it’s important that they can wiggle without hitting the shoe.

How to measure your feet
Put on a pair of socks usually worn with the shoe and measure your feet in the afternoon (often, the feet swell during the course of the day). Stand on ones feet on hard surface and position a sheet of paper under your foot. Distribute your weight in a uniform fashion. Measure from the border of the sheet of paper under the heel to tip of the foot, which more or less is the second toe (as seen in the photo). Use a ruler to measure the length taken in centimetres.