What an infinity scarf is and why it's easier than you think

An infinity scarf is a loop of knitted fabric with no beginning or end — you wear it wrapped around your neck once or twice, and the seam is hidden inside the loop. The reason knitters often choose this project is straightforward: it's a rectangle sewn into a circle, which means you can knit in stockinette stitch (the most basic stitch pattern) from start to finish without shaping, decreasing, or binding off anything except the final edge. If you can cast on, knit, purl, and bind off, you can make an infinity scarf.

The finished scarf is warmer than a regular scarf because the loop traps air and stays in place without sliding. It also looks intentional — no loose ends flapping around. Most infinity scarves take between one and three weeks to knit, depending on how often you work on them and how wide you make the rectangle.

Key Takeaways

  • An infinity scarf is a rectangle of knitting sewn into a loop, so you only need to master basic stitches and never shape the fabric.
  • Most patterns call for worsted-weight yarn and size 8 to 10 needles, and the rectangle is usually 60 to 70 inches long and 8 to 12 inches wide.
  • You knit in stockinette stitch (knit on the front, purl on the back) until the rectangle reaches the right length, then bind off and sew the short ends together.
  • The seam should be sewn with mattress stitch on the inside of the loop so it doesn't show when you wear it.
  • Blocking the finished scarf before you sew it makes the edges straighter and the fabric more even.

Choosing yarn weight and needle size

Worsted-weight yarn (also called medium or #4 weight) is the standard choice for infinity scarves because it knits up quickly and drapes well without being too heavy. Bulky yarn (#5 weight) works too and finishes even faster, but the scarf can feel stiff. Lighter weights like DK or sport yarn take longer and may feel thin around your neck.

Match your needle size to the yarn label's recommendation — usually size 8 to 10 US needles for worsted weight. If you knit tightly, go up a size; if you knit loosely, go down a size. The goal is fabric that feels soft and has a little give when you stretch it gently. You'll need enough yarn to knit a rectangle roughly 60 to 70 inches long and 8 to 12 inches wide. A 400-yard skein of worsted weight is usually enough; if you're unsure, buy two skeins.

Casting on and planning your rectangle

Cast on a number of stitches equal to the width you want. For an 8-inch-wide scarf, cast on 32 stitches (roughly 4 stitches per inch in worsted weight). For 10 inches, cast on 40 stitches. For 12 inches, cast on 48 stitches. If you're not sure how many stitches per inch your yarn knits at, knit a small swatch first — cast on 20 stitches, knit 20 rows in stockinette, bind off, measure it, and do the math.

Write down your target length before you start. Most infinity scarves are between 60 and 70 inches long. At roughly 4 rows per inch in worsted weight, a 60-inch scarf needs about 240 rows. A 70-inch scarf needs about 280 rows. You don't have to count every row — just measure the rectangle against a ruler or measuring tape every 10 rows or so, and stop when you reach your target length.

Knitting in stockinette stitch

Stockinette stitch is knit on the front (right side) and purl on the back (wrong side). This creates the smooth, V-shaped texture you see on most scarves. Cast on, then knit the first row. On the second row, purl across. Repeat: knit one row, purl one row, for as many rows as you need.

The only variation most patterns use is a garter-stitch border — knitting the first and last stitch of every row instead of purling them. This creates a chain-like edge that looks finished and is easier to sew. If you want this, knit the first stitch and the last stitch of every row, and purl or knit the middle stitches depending on which side you're on.

Keep the tension even as you work. If your stitches get tighter or looser as you go, the scarf will look wavy. A good habit is to check your tension every 10 rows by laying the scarf flat and looking at the width — it should stay the same.

Binding off and blocking

When your rectangle reaches the target length, bind off all stitches. Use the standard bind-off: knit two stitches, pass the first stitch over the second, knit one more stitch, pass the first over the second, and repeat until one stitch remains. Cut the yarn, pull it through the last stitch, and weave in the end.

Blocking is optional but worth doing. Wet the finished rectangle in cool water, squeeze out the excess gently (don't wring it), and lay it flat on a towel to dry. This evens out the stitches and straightens the edges, making the seam easier to sew and less visible. It takes 24 hours to dry completely.

Sewing the seam with mattress stitch

Lay the rectangle flat with the right side facing up. Fold it in half lengthwise so the two short ends meet. The right sides should be facing out and the wrong sides should be facing in — this way, the seam will be hidden inside the loop.

Thread a tapestry needle with yarn that matches your scarf. Mattress stitch is the best seam for this because it's nearly invisible. Working from the inside of the fold, insert the needle under the first stitch on one side, then under the corresponding stitch on the other side. Move up one row and repeat, going back and forth between the two sides. Pull the yarn snug every few stitches so the seam closes. When you reach the end, weave in the yarn end and gently stretch the loop to even out the seam.

If mattress stitch feels unfamiliar, a backstitch seam works too — it's less invisible but faster. Insert the needle through both layers, move forward one stitch, and insert again, going back to close the gap. The result is a visible seam, but it's sturdy.

Finishing touches and wearing your scarf

Once the seam is sewn, weave in any remaining yarn ends on the inside of the loop. Try the scarf on — wrap it around your neck once for a single loop, or twice for a double loop. If it feels too long or too short, you can unravel the seam, knit or unravel a few more rows, and resew it.

If the edges curl slightly, a light steam with an iron on low heat (hold it a few inches above the fabric, don't press down) can help. Some yarns curl more than others, and this is normal. A garter-stitch border or a few rows of garter stitch at the top and bottom of the rectangle can prevent curling entirely.

Frequently Asked Questions

Can I use a different stitch pattern instead of stockinette?

Yes. Garter stitch (knit every row) is thicker and warmer but takes longer. Ribbed patterns (alternating knit and purl columns) stretch more and feel snug. Seed stitch (alternating single knits and purls) looks textured. Any stitch pattern works as long as you keep the same number of stitches throughout — no increasing or decreasing.

What if my scarf curls at the edges?

Stockinette naturally curls because knit stitches pull inward. Add a garter-stitch border by knitting the first and last 3 to 5 stitches of every row, or knit 4 to 6 rows of garter stitch at the beginning and end. Blocking with steam also helps flatten the edges.

How do I fix a mistake if I notice it several rows later?

If it's a single dropped stitch, use a crochet hook to pick it up and pull it back through the rows above. If it's a twisted stitch or a purl where a knit should be, you can unravel back to that row, fix it, and knit forward again. For small mistakes in the middle of the scarf that don't affect the structure, many knitters leave them — they're usually invisible when worn.

Do I need to block the scarf before sewing?

Blocking is not required, but it makes the seam straighter and less visible. If you skip it, the scarf will still work — blocking just makes it look more polished. If you do block, let it dry completely before sewing.

Can I make the scarf wider or narrower?

Yes. Cast on more stitches for a wider scarf, fewer for a narrower one. Just remember to adjust your row count — a wider scarf needs more rows to reach the same length. Measure as you go and stop when the rectangle feels like the right size to wrap around your neck comfortably.