Ready to cut your knitting? This tutorial is for a true afterthought heel - one where you measure to the correct spot, and then follow the instructions below to begin to insert the heel.
If you're wondering why I don't knit a line of waste yarn into the sock at the correct height, it's because that is called a forethought heel, because (as the name suggests) it requires forethought to plan the heel placement.
With an afterthought heel, you can knit the foot and leg as long as you'd like without having to measure for heel placement.
Need a full afterthought heel pattern that will fit the whole family?
Photo 1: At the correct height, insert your needle into the right side of all the sole stitches in one row (you should pick up half the stitch count of the whole sock). Then, do the same thing two rows up with the other needle. You should have an entire row of stitches between the two picked up rows.
Photo 2: Pick a middle stitch in the skipped row (where no stitches were picked up), and cut it.
Photo 3: Use a yarn needle to begin unraveling the stitches to the left and right of the cut stitch. Do NOT unravel the last 2 stitches on either side of the row.
Photos 4 & 5: This is how each side should look when you are done unraveling. 4 stitches total are left as they were. They will be knit as normal with the rest of the heel, but leaving them attached will prevent a hole in the side of the heel.
To complete the heel, knit as you would knit a toe and graft it shut.