I posted this as an answer in another thread, but thought some folks might find this useful:
It’s hard to know exactly how long to knit the foot of socks, before beginning the toe. If it’s your own foot, or not a gift, then the easiest thing to do is to stand on a large piece of paper and have someone closely trace the foot and then measure the length.
But if it’s a surprise gift, then that’s not an option. This chart http://www.i18nguy.com/l10n/shoes.html has the measurements for every adult size in every country, men and women. It’s a little complicated to read, but it works.
Lower down on this page http://www.bevscountrycottage.com/size-chart.html#foot is a chart for babies’ feet, plus some other useful measurements.
Most patterns tell you to knit the foot length leaving a certain amount of space for the toe finishing, usually 2". But if they don’t, then
- Go to another part of the sock which was knitted in stockinette stitch.
- Measure the number or rows/rounds you’re getting per inch. Let’s say that’s 10.
- Figure out how many rows/rounds you need for the toe. Let’s say they say decrease every other row/round, for 20 rounds and then graft the toe. Those 20 rows/rounds will give you 2 more inches, so that’s how much you need to leave off of your foot length.
Of course, the numbers aren’t usually quite so nice, but you get the idea.