Nike React Infinity Run Flyknit Racer Blue/White/Bright Crimson/Black

Choose by centimeters (CM)
If you are buying this model for the first time, we suggest you choose the size based on the length (in centimeters) of your foot. Choose the size keeping in mind that it is advisable to leave about one centimeter of space at the tip of the shoe, since during the run the foot tends to swell due to the increase in circulation. This means it is recommended to leave the toes free to move without touching the tip of 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.