Young Brunette Girl Wearing Yellow Socks On The Chair At Home

In the United Kingdom, a sock's size is similar to the person's shoe size; for example, a foot that has a shoe size of 9 would require a sock sized 8-10.
In some other parts of the world socks are sized differently than shoes. In the U.S. numerical sock size is the length of the foot in inches, whereas shoe size is not.
Sock lengths vary, from ankle-high to thigh level.