Circular needles work better for socks than straight needles because you cast on all your stitches at once and knit in continuous rounds

A circular needle is two short needle tips connected by a flexible cable. For socks, you cast on your stitches (usually 60 to 80, depending on foot size) onto the cable, then distribute them between the two needle tips. You knit around and around without turning your work, which means the right side of your fabric always faces you. This produces a seamless tube that fits a foot better than a sock sewn from flat pieces.

You will need a circular needle sized 1 to 3 (2.25 to 3.25 mm) with a cable length of 16 inches or shorter — a 24-inch cable is too long and makes the stitches bunch. Yarn weight matters: most sock patterns call for fingering weight (also labeled "sock weight"), which is thin enough to fit inside a shoe without bulk. Worsted weight or thicker will produce a slipper, not a sock.

Key Takeaways

  • Cast on 60 to 80 stitches using long-tail cast-on, then join them into a circle without twisting the stitches.
  • Knit the cuff (usually 1 to 2 inches of ribbing) before moving to the leg, which is stockinette stitch until you reach the heel.
  • The heel is worked flat on half your stitches while the other half rests, then you pick up stitches along the heel flap to rejoin the round.
  • The foot is knit in stockinette until you are about 2 inches from your target length, then you decrease stitches to close the toe.
  • Weave in the yarn ends and try the sock on — it should fit snug but not tight, with no wrinkles at the heel or toe.

Cast on and join without twisting

Use the long-tail cast-on method: measure out a tail about three times the width of your needle, make a loop, and cast on your stitches one by one. For a medium adult foot, cast on 64 stitches. Slide all the stitches onto the cable so they sit evenly around the entire length — do not bunch them on one needle tip.

Before you knit the first stitch, check that your cast-on edge is not twisted. Lay the circle flat on a table and look at the bumps along the cast-on edge. They should all face the same direction, toward the center of the circle. If any bumps face outward, you have twisted the stitches. Unwind back to the twist, straighten it, and continue. A twisted cast-on cannot be fixed once you start knitting.

Place a stitch marker on your working yarn (the yarn attached to the ball) to mark the start of the round. Knit the first stitch using the tail end and the working yarn together — this joins the circle. From that point forward, you knit continuously in a spiral.

Knit the cuff and leg in ribbing and stockinette

The cuff is usually 1 to 2 inches of ribbing, which is alternating knit and purl stitches (K1, P1 or K2, P2, depending on your pattern). Ribbing stretches and grips the ankle. Knit the ribbing for the number of rounds your pattern specifies — count by marking every tenth round with a safety pin if you lose track.

After the cuff, switch to stockinette stitch (knit every round) for the leg. This is the straightforward part: you knit in rounds until the leg reaches the height you want, usually 6 to 8 inches for an adult. Measure against your own leg or the person you are knitting for. The leg should reach just below the calf.

As you knit, the tube will grow downward from your needles. Every 10 to 15 rounds, slide the stitches down the cable so they do not bunch at the needle tips. This also prevents the cable from kinking.

Work the heel flap flat on half your stitches

When your leg is the right length, you are ready to knit the heel. The heel is the only part of the sock worked flat (back and forth) rather than in rounds. Divide your stitches in half: if you cast on 64, you now have 32 stitches for the heel and 32 for the instep (the top of the foot).

Slip the instep stitches onto a spare needle or stitch holder and set them aside. You will work only the heel stitches. Attach your yarn at the edge of the heel stitches and knit back and forth in stockinette for about 2 inches (roughly 16 to 20 rows). This creates a small flat rectangle.

On the last row of the heel flap, you will turn the heel by decreasing stitches in a specific pattern. Most patterns use a method called a "short-row heel" or a "wedge heel." Follow your pattern's exact instructions for the decreases, as the placement matters. The goal is to reduce your 32 heel stitches down to about 16 to 20 stitches that form a small cup shape.

Pick up stitches along the heel flap to rejoin the round

After you have turned the heel, you pick up stitches along the sides of the heel flap to rejoin the instep stitches and return to knitting in rounds. This is where many knitters get stuck, so work slowly.

With the heel cup facing you, pick up one stitch in each row along the left side of the heel flap (you should pick up about 10 to 12 stitches). Then knit across the instep stitches that have been waiting on the spare needle. Then pick up one stitch in each row along the right side of the heel flap. You now have roughly 60 to 70 stitches on your needles again.

The stitches you picked up are often loose. On the next round, knit into the back loop of each picked-up stitch — this tightens them. You are now knitting in rounds again, and the heel is complete.

Knit the foot and decrease for the toe

Knit in stockinette stitch (knit every round) until the foot is about 2 inches shorter than your target length. For an adult, this is usually around 7 to 8 inches from the back of the heel. Measure the sock against the foot it will go on, or measure a sock that fits well.

When you reach the right length, begin the toe decreases. Most patterns use a "wedge toe" or "star toe," which means you decrease 4 to 8 stitches every other round by knitting two stitches together at set intervals around the foot. Follow your pattern's decrease sequence exactly — the placement keeps the toe centered and symmetrical.

Keep decreasing every other round until you have about 8 to 12 stitches left. Cut the yarn, thread it through a tapestry needle, and pull it through the remaining stitches to close the toe. Pull tight and weave the yarn end into the inside of the sock.

Weave in ends and check the fit

You now have a complete sock. Weave the cast-on tail and any other loose ends into the inside of the sock using a tapestry needle. Work the needle through the bumps of the stitches for about an inch, then trim the yarn close to the fabric.

Try the sock on. It should fit snug around the foot and ankle without cutting off circulation. The heel should sit at the back of your heel with no wrinkles or bunching. The toe should have a little room — you should be able to wiggle your toes. If the sock is too loose, you may have cast on too many stitches or used a needle that was too large. If it is too tight, the opposite is true.

Wash the sock in cool water with mild soap, squeeze out the water (do not wring), and lay it flat to dry. Once it is dry, knit the second sock using the same pattern and yarn.

Frequently Asked Questions

What size circular needle do I need for socks?

Use a needle sized 1 to 3 (2.25 to 3.25 mm) with a cable length of 16 inches or shorter. A 24-inch cable is too long and makes the stitches bunch. The exact size depends on your yarn weight and how tightly you knit — check your pattern's recommendation.

Can I use straight needles instead of circular needles?

You can, but it is more difficult. Straight needles require you to knit the sock in flat pieces and sew them together, which creates seams inside the shoe. Circular needles produce a seamless tube that fits better and is faster to knit.

How do I know what size sock to knit?

Measure the foot circumference at the widest part (usually across the ball of the foot) and multiply by 0.9 to get your cast-on number. For example, a 9-inch foot needs about 64 stitches. Most patterns give a finished circumference, so choose the size closest to your measurement.

What do I do if I drop a stitch in the middle of the leg?

Stop knitting as soon as you notice it. Use a crochet hook to pick up the dropped stitch by pulling the loose loops through it, one at a time, until the stitch is back on your needle. If the dropped stitch is more than a few rows down, you may need to unravel back to that point.

How long does it take to knit a pair of socks?

A pair usually takes 15 to 25 hours, depending on your speed and the yarn weight. Fingering-weight socks take longer than thicker yarn. Many knitters knit one sock while watching television or commuting, then knit the second sock later.