The following measurements are for crew-style or dress socks, which usually come several inches above the ankle and below the calf.
11a. Foot Circumference: To determine the foot circumference, measure around the widest part of your foot.
11b. Sock Height: To determine the height of the sock, measure from where you start to turn for the heel shaping to the top of the sock.
11c. Total Foot Length: To measure the total length of your foot, place a ruler or tape measure on the floor. Position the back of your heel at the beginning of the tape and the measure to your longest toe.
NOTE ABOUT SOCK SIZING: In our charts we only refer to U.S. sizes and in the U.S. sock size ranges overlap. In addition, sock sizes do not correlate to shoe size.
NOTE ABOUT PRINTING THIS CHART: While easy to read on your computer screen, the above chart will be slightly bit mapped when printed. For a sharper copy, print out the standards document pdf.
Source: Craft Yarn Council of America’s www.YarnStandards.com