HOW TO TAKE MEASUREMENTS
First, get a ruler, a sheet of paper and a pen.
Put socks on and stand against the wall on a sheet of paper.
Be sure to keep your heel firmly against the wall and your flat foot on the sheet.
Draw a line in front of the end of your big toe.
Measure the distance in cm from the edge of the sheet to the line. Round to the nearest millimeter.
NB: Sizes may vary by brand.