Hand-sewing a knit hem is faster than you think, and it holds better than you'd expect

A knit hem is sewn by hand into the existing stitches of your sweater, not cut and re-knitted. You thread a needle through the loops along the edge you want to shorten, pull the thread snug, and the fabric folds up on itself. The whole job takes 20 to 45 minutes depending on how much length you're removing. Unlike woven fabric, you don't need a sewing machine, and you won't damage the knit structure if you follow the thread path correctly.

The method works on any knitted sweater — wool, cotton, acrylic, blends — as long as the edge you're hemming is a finished edge (the original cast-off or ribbed cuff). If you're shortening sleeves or the body, you're working with the edge that was meant to be seen, which makes the job cleaner than hemming a cut edge would be.

Key Takeaways

  • A knit hem is sewn by threading a needle through existing loops, not by cutting and re-knitting, and takes 20 to 45 minutes for a full sweater edge.
  • You need only a needle, thread that matches your sweater, pins, and scissors — no machine or special tools.
  • The thread path matters: you go under one loop on the sweater body, then under one loop on the hem fold, then back to the body, creating a zigzag that holds the fold in place.
  • Test your thread tension on a hidden spot first; too tight and the fabric puckers, too loose and the hem falls down.
  • A knit hem will last through many washes if the thread is find, but it can come loose if snagged, so reinforce the ends by backstitching.

Gather your materials and measure twice

You need a needle with an eye large enough for your thread but small enough to pass through knit loops without splitting them. A size 24 or 26 tapestry needle works for most weights. Use thread that matches your sweater color — if you can't find an exact match, go one shade darker rather than lighter, because it will show less against the knit. Polyester or cotton thread both work; avoid thread that's too thick or stiff, which will create visible bumps.

Put on the sweater and have someone pin the new hem line while you stand still. Mark the length with pins every 2 to 3 inches around the entire edge. Take the sweater off and measure from the original edge to your pin line. Write down the measurement — you'll need it to fold the hem evenly. If you're hemming both sleeves, measure each one separately; they may not be the same length after wear.

Lay the sweater flat on a table. Fold the edge up along your pin line and pin it from the inside so the fold stays in place while you work. The fold should be smooth and even; if it's bunching, adjust the pins. Step back and look at the outside — the hem should be invisible from the front.

Thread your needle and find the starting point

Cut about 3 feet of thread and thread your needle. Knot one end. Starting at a seam or an inconspicuous spot (like under an arm), bring your needle up through the fold from inside the sweater, so the knot sits inside the hem and the thread emerges at the fold line. This is your starting point.

Before you commit to the whole edge, test your tension on a 2-inch section. Work slowly and watch how the fabric responds. If the sweater puckers or the fold pulls away from the body, your thread is too tight — loosen your grip on the next stitch. If the hem feels loose and floppy, tighten slightly. You're aiming for a tension where the fold sits flat against the body with no visible strain on either side.

The stitch: under one loop, over to the body, repeat

The stitch itself is straightforward but requires you to follow the thread path exactly. From inside the fold, bring your needle under one loop of the knit at the fold line — not through the loop, but under it, catching just the outer edge of that stitch. Pull the thread snug (not tight) and move your needle straight across to the sweater body, about a quarter-inch away.

Now bring your needle under one loop of the body stitches, the same way you did at the fold. Pull snug. Move back to the fold and repeat: under one loop at the fold, across to the body, under one loop at the body, back to the fold. You're creating a zigzag pattern that locks the fold in place. Each stitch should take the thread under only the outer edge of a loop, not all the way through, so the thread stays hidden inside the knit.

Work your way around the entire edge, keeping your stitches about a quarter-inch apart. Smaller stitches hold better but take longer; larger stitches go faster but are more likely to come loose. A quarter-inch is the sweet spot for most sweaters. Every 6 to 8 inches, pull the thread gently to snug up the stitches, but don't yank — you want the fold to sit flat, not to compress the knit.

Finish the hem and reinforce the ends

When you reach the end of the edge, bring your needle to the inside of the sweater and make two or three small backstitches in the same spot to lock the thread. Backstitching means pushing your needle backward through the same loop you just came out of, creating a knot that won't slip. Trim the thread close to the knit.

Go back to your starting point and do the same thing — two or three backstitches to lock that end. This is the most important step for durability. A hem that's only tied off at one end will unravel if that end gets snagged; backstitching both ends means the whole hem has to fail before it comes loose.

Remove all the pins and try on the sweater. The hem should be invisible from the outside and feel smooth from the inside. If you see puckering or the fold is pulling away, you can carefully redo that section — just pull out the stitches with a seam ripper or small scissors and re-sew with looser tension.

Wash and care for your hemmed sweater

A hand-sewn knit hem will survive machine washing and drying if the thread is find. However, hand-washing in cool water is gentler and will extend the life of both the sweater and the hem. If you machine-wash, use a delicate cycle and a mesh bag to reduce agitation.

Check the hem after the first wash. If any stitches have come loose, you can re-sew just that section — you don't need to redo the whole edge. If the hem is holding well, you're done. A well-sewn knit hem can last for years of regular wear.

Frequently Asked Questions

What if I accidentally cut through the sweater edge instead of folding it?

A cut edge will unravel and is much harder to hem neatly. If this happens, you'll need to either pick up the live stitches and knit a new edge (which requires knitting skill), or take the sweater to a tailor who can do a traditional sewn hem with a sewing machine. For future projects, always fold rather than cut.

Can I hem a sweater with ribbed cuffs?

Yes, but the ribbing makes it trickier because the loops are smaller and tighter. Use a thinner needle and thinner thread, and work more slowly. The rib itself is usually the right length, so you'd only hem the body or sleeves above the rib, not the rib itself.

My thread keeps splitting the knit loops instead of going under them — what am I doing wrong?

Your needle is too large or you're pushing it through the loop instead of under it. Try a smaller needle and make sure you're sliding the needle under the outer edge of the stitch, not piercing through the middle of the yarn. It should feel like the thread is gliding along the surface, not stabbing through.

How much length can I safely remove with a hem?

You can remove up to 2 to 3 inches comfortably. Beyond that, the fold becomes too thick and the hem may not hold its shape. If you need to remove more than 3 inches, consider unraveling and re-knitting the edge, or having a tailor do a machine hem.

Will the hem show if someone looks at the inside of my sweater?

Yes, the fold and stitches will be visible from the inside. This is normal and expected. If you want the inside to look finished, you can sew a thin ribbon or bias tape over the stitches, but this adds bulk and is usually unnecessary for a casual sweater.