Converting Shoe Size to Sock Length

Looking at a shoe or foot size chart for knitting gift socks can be very confusing, at least to me. If a foot is 9 inches long, how does that translate into length of a sock measured flat?

I have women of all shoe sizes in my family. Here is a sock size chart I keep in my sock notebook based on my experience knitting for them.

The measurement listed and number of rows listed is the length from the gusset pickup row to the beginning of the toe decreases.

The number of rows given is for my sock knitting gauge of 10 rows per inch. If your sock knitting gauge is different and you want to count rows, you will need to recalculate.

Shoe size 6, 6 inches, 60 rows
Shoe size 7, 6.4 inches, 64 rows
Shoe size 8, 6.7 inches, 67 rows
Shoe size 9, 7 inches, 70 rows
Shoe size 10, 7.4 inches, 74 rows
Shoe size 11, 7.7 inches, 77 rows
Shoe size 12, 8 inches, 80 rows