The leg is about 13cm long to the top of the heel flap. The charted pattern continues to the toe decreases, for a foot of about 20.3 cm (medium women's).
The cuff starts with a tubular cast-on. I found the cast-on rows too tight when I used the Size 3 needle, so I switched up a size. If your tubular cast-on runs loose, or you decide to use another cast-on, you won't need the Size 4 needles.
The chart is a little long for letter-size paper, so you may want to print it out on US Legal paper.