The heel is where a sock gets its shape and durability

A sock heel is not a separate piece sewn on—it is a section of the sock you knit by working back and forth on a subset of your stitches, turning your work partway through each row to create a wedge shape. This technique, called a heel turn, lets you angle the foot down from the leg so the sock sits properly on your foot. The most common method is the short-row heel or flap-and-gusset heel, depending on whether you want a reinforced flap running up the back of your leg or a simpler construction.

The process takes about 20 to 30 rows and uses only half your stitches at a time. Once you have turned the heel, you pick up stitches along the sides to close the gap and return to knitting in the round for the foot. It sounds more complicated than it is—the same logic repeats for each row.

Key Takeaways

  • A heel turn is made by knitting back and forth on roughly half your stitches, decreasing at the edges to create a wedge that angles the foot downward.
  • The flap-and-gusset method is the most common: you knit a flat rectangular flap, turn the heel, then pick up stitches along the flap sides to close the gap.
  • Short-row heels use wrapped stitches instead of a flap and are faster but less durable for heavy wear.
  • You will need to know how to work a decrease (knit two together or slip-slip-knit) and how to pick up stitches from the edge of your work.

Setting up the heel flap

Before you turn the heel, you divide your stitches. If you have 64 stitches around your leg, roughly half (32) will form the heel flap and the other half will stay on a holder or spare needle for now. Slip those 32 stitches to a spare needle and set them aside—they will become the instep (top of the foot) later.

Work the heel flap on the remaining 32 stitches by knitting flat (back and forth) instead of in the round. Most patterns call for a slipped-stitch edge: on every row, slip the first stitch knitwise and knit the last stitch. This makes the edge neat and easier to pick up stitches from later. Knit stockinette stitch (knit on the right side, purl on the wrong side) for 24 to 32 rows, depending on your yarn weight and how tall you want the flap. A good rule is to knit until the flap is roughly as wide as it is tall.

Working the heel turn with decreases

The heel turn is where the wedge shape happens. You will work on only part of your stitches each row, leaving the others unworked. This creates a gap that you close later by picking up stitches.

Divide your heel flap stitches into three sections. If you have 32 stitches, that is roughly 11, 10, and 11. On the first row of the turn, knit across 11 stitches (the first section), knit 2 together, knit 1, then turn your work without finishing the row. The stitches you did not knit stay on the needle.

On the next row, slip 1 stitch, purl back across the stitches you just worked, purl 2 together, purl 1, then turn again. You are now working one stitch fewer each row. Repeat this pattern—knit across, decrease, turn; purl across, decrease, turn—until you have worked down to just the middle section of stitches (roughly 10 stitches). You now have a wedge-shaped heel.

Picking up stitches along the flap edge

Once the heel turn is complete, you need to close the gap on both sides. You do this by picking up stitches along the edge of the flap you just knitted. With your working yarn, pick up one stitch in each slipped stitch along the left side of the flap. If your flap was 24 rows, you should pick up roughly 12 stitches (one for every two rows, since slipped stitches are taller than they are wide).

Knit across the heel stitches (the wedge you just turned), then pick up the same number of stitches along the right side of the flap. You now have stitches on your needle in this order: picked-up stitches on the left, heel stitches in the middle, picked-up stitches on the right, and the instep stitches still waiting on a spare needle.

Closing the gusset

You are now back to knitting in the round, but you have extra stitches from the pickup. The gusset is the wedge-shaped section on the sides of the foot where these extra stitches live. You decrease them away over the next few rounds until you are back to your original stitch count.

On the first round, knit the left picked-up stitches, knit the heel stitches, knit the right picked-up stitches, then knit the instep stitches. On the next round, knit to the last 3 stitches of the right picked-up section, knit 2 together, knit 1. Then knit the instep. On the following round, knit 1, slip-slip-knit (or another left-leaning decrease), then knit to the end. Alternate these decreases on each side until the gusset stitches are gone and you are back to your original stitch count.

Short-row heels as an alternative

If you want a faster heel without a flap, a short-row heel uses wrapped stitches instead. You knit back and forth on half your stitches, wrapping the stitch where you turn to avoid leaving a hole. After you have worked the wedge, you unwrap those stitches and knit them together with their wraps on the way back up.

Short-row heels are less durable than flap-and-gusset heels because there is no reinforced flap to absorb wear. They work well for lighter socks or dress socks, but if you are knitting everyday socks, a flap is worth the extra rows.

Common mistakes and how to avoid them

The most common error is picking up too many or too few stitches along the flap edge. Count your slipped stitches before you start—if your flap is 24 rows, pick up 12 stitches (one for every two rows). Picking up too many creates a loose, baggy gusset; too few leaves holes.

Another mistake is forgetting to decrease the gusset stitches. If you skip this step, your sock will have a bulge on the sides of the foot and will not fit properly. Work the decreases on every round or every other round until the gusset is gone.

Finally, make sure your heel turn stitches are tight. If you are loose with your decreases, the heel will stretch out quickly. Pull your yarn snug when you work the knit 2 together and slip-slip-knit decreases.

Frequently Asked Questions

What is the difference between a flap-and-gusset heel and a short-row heel?

A flap-and-gusset heel has a reinforced rectangular flap running up the back of the leg, making it more durable for everyday wear. A short-row heel is faster and uses wrapped stitches instead of a flap, but it is less sturdy and better suited to lighter socks.

How many rows should the heel flap be?

Aim for a flap that is roughly as wide as it is tall. For most sock yarns, that is 24 to 32 rows. If you are unsure, knit until the flap reaches from your ankle bone to about an inch below your calf.

What if I drop a stitch while picking up stitches along the flap?

Stop and pick it up right away with a crochet hook. Insert the hook through the dropped stitch from front to back, catch the horizontal strand of yarn above it, and pull through. Do this for each row until the stitch is caught back up.

Can I use a different decrease for the gusset?

Yes. Knit 2 together and slip-slip-knit are the most common, but any decrease works. Just make sure you use a left-leaning decrease on one side and a right-leaning decrease on the other so the decreases slant away from the center and look balanced.

How do I know when the gusset is fully decreased?

You are done when your stitch count matches what you had before the heel—usually the same number you cast on for the leg. Count your stitches if you are unsure, or mark your original count on a stitch marker before you start the heel.