How to Hem a Knitted Sweater

You can hem a knitted sweater by folding and sewing the existing edge, or, if you need to shorten it and can lose the ribbing, by stabilizing the cut line with fusible hem tape before cutting. The key is to support the stretchy knit while you sew so the hem does not ripple, tunnel, or pull out of shape. Choose a method based on whether you are preserving the original bottom band, removing length, or working without a sewing machine.

What Makes a Knitted Sweater Hard to Hem

A sweater is made from interlocking loops rather than a woven fabric. When those loops are cut, some knits can unravel or “run,” especially at a raw lower edge. Knit fabric also stretches as it passes under a sewing-machine presser foot, which is why an otherwise straight hem can come out wavy.

The bottom edge of a sweater is called the hem. If it has a ribbed band, that band may also be called the bottom band or ribbing. Ribbing is designed to spring back and hold its shape, so it is more difficult to alter neatly than a plain knit edge.

Before you begin, inspect the sweater:

Check the fiber content and care label.
Look at the hem construction. A thin, plain, curved, split, or tied hem is easier to replace than a deep ribbed band.
Try the sweater on and mark the finished length while standing naturally. A sweater can look much shorter when you lift your arms or sit down.
Decide whether you are comfortable losing the original ribbing. Cutting it off is permanent.

How to Hem a Knitted Sweater With a Folded, Sewn Hem

Use a tape-stabilized cut-and-fold hem when the sweater needs shortening.

This method works especially well on sweaters with curved hems, side splits, ties, or narrow ribbing. It creates a clean new hem.

Your Goal	Best Method	Important Watch-Out
Shorten a plain, curved, split, or tied hem	Fuse hem tape at the cut line, trim below it, fold, then sew	The original ribbing will be removed
Keep the current length but tidy a loose edge	Fold the existing edge inward and hand sew it	Avoid pulling the stitches tight
Shorten a sweater while preserving a substantial ribbed band	Have the ribbing removed and reattached, or reknit the lower section	Cutting above or through ribbing can permanently change the sweater’s shape
Make a stretchy machine-sewn hem	Use fusible web for stability and a ballpoint twin needle	Test the stitch on a scrap before sewing the sweater

Step 1: Mark the Finished Length

Put the sweater on over the type of clothing you expect to wear with it.
Fold the lower edge upward until the sweater reaches the length you want.
Mark that finished level around the sweater’s wrong side, using pins or a fabric-safe marking tool.
Lay the sweater flat without stretching it, and compare the front, back, and side seams to make sure the marks are level.

I use a fabric marking pencil for this line because it is easier to see on the wrong side of a knit than a row of pins.

If the sweater has a shaped hem, do not force it into a straight line. Preserve the curve by marking the same shape at the new length.

Step 2: Calculate and Stabilize the Cut Line

The hem tape becomes the turned-up hem allowance, so allow for its width before cutting. With 5/8-inch hem tape, subtract 5/8 inch from the total amount you want to shorten; the result is the amount to cut away.

For example, if you want the sweater to be 2 inches shorter, cut away 1 3/8 inches. The remaining 5/8 inch turns up to form the new hem.

Work on the wrong side of the sweater.
Mark the cutting line evenly around the garment.
Place backed fusible hem tape directly above that cutting line, keeping the tape smooth and following any curve in the hem.
Fuse the tape to the sweater with an iron, after first testing the heat on an inconspicuous area.

A backed fusible web needs a 2-step process: first fuse it to stabilize the cut line; then, after cutting and removing the paper backing, fuse the folded hem in place.

Let the tape cool completely. Then cut away the excess sweater below the tape, taking care not to nick the tape itself. The tape holds the knit loops at the edge and reduces the risk of the cut edge beginning to run.

For a pronounced curve, cut the tape into short pieces so it can follow the shape without buckling.

Step 3: Fold and Fuse the New Hem

Peel away the paper backing from the cooled hem tape.
Turn the taped edge to the wrong side so the tape sits inside the fold.
Fold up the 5/8-inch allowance evenly all the way around.
Fuse the fold in place, working in small sections and keeping the sweater relaxed rather than stretched.

The tape makes the hem temporarily firm enough to sew neatly. It is useful stabilization, not a substitute for stitching a hem that will be worn and washed.

If you are using fusible web without a paper backing for a hem that does not need cutting, sandwich the web completely inside the folded edge before pressing. No exposed web should touch the iron.

Step 4: Set Up the Sewing Machine

Install a ballpoint twin needle rather than a standard sharp needle. A ballpoint point slips between knit loops instead of piercing and damaging them.

A size 80 ballpoint twin needle with needles spaced 4.0 mm apart is a practical starting configuration for a comparable sweater knit, but it is not universal. Test it on a piece cut from the hem or another piece of similar knit fabric before sewing the garment.

Thread the machine for twin-needle sewing.
Turn on the machine’s twin-needle setting if it has one.
Set the upper tension a little looser than your usual setting.
Test the stitch on a scrap. The right side should show two even rows of straight stitching, while the underside forms a zigzag that lets the hem stretch.

If the test seam pulls, tunnels between the two needle lines, or breaks when gently stretched, adjust the tension or needle choice before sewing the sweater.

Step 5: Sew and Finish the Hem

Place the sweater right side up, keeping the folded hem flat and using the guide markings on your machine to keep the stitching even.
Sew slowly around the hem, keeping the twin-needle stitching an even distance from the folded edge.
Do not tug the sweater from the front or back as you sew. Let the feed dogs move the knit through the machine.
Leave long thread tails at the start and finish rather than making a bulky backstitch.
Thread each tail into a hand-sewing needle and bury it inside the hem for a couple of inches before trimming.

Give the hem a gentle stretch after sewing if it feels stiff. The knit’s natural springiness should return, and any remaining stiffness usually eases after the sweater is washed as it normally would be.

How to Hand-Sew a Sweater Hem

Hand sewing is the quieter, lower-risk option when you do not have a machine or when the sweater already has a finished bottom edge that can be folded inside. It is best for a modest adjustment rather than removing a large amount of length.

Turn the sweater inside out and mark the desired finished length.
Fold the existing finished edge inward to that level, distributing the excess evenly around the sweater.
Pin or baste the fold in place without stretching the knit.
Thread a hand-sewing needle with matching sewing thread for a fine commercial sweater, or matching yarn for a hand-knit sweater if the yarn will not create bulk.
Start near a side seam and use small, loose slip stitches to catch the folded hem and a tiny amount of the sweater body.
Keep the stitches evenly spaced and relaxed. Pulling the thread tight will make the hem pucker and reduce stretch.
Secure the thread tails inside the fold, trim them, and remove the pins or basting thread.

A slip stitch is usually the least visible hand stitch for a sweater hem. A loose herringbone or catch stitch can add more flexibility, but it may show slightly on a thin knit.

Folding a finished edge inward can shorten the visible length. That is helpful for a small adjustment, but it can become bulky with thick ribbing or heavy yarn.

How to Keep the Original Ribbing

A deep ribbed bottom band is not simply a hem allowance. It needs different handling from a plain folded hem.

The cleanest permanent alteration is to shorten the sweater body and reattach the ribbing, or to unravel and reknit the lower portion if you have matching yarn and the knitting skills.

For a valuable hand-knit sweater, a favorite ribbed sweater, or a garment with a complicated cable or colorwork pattern near the hem, a knitwear alteration specialist is often the safer choice. A folded hand-sewn hem is a practical at-home compromise.

How to Flatten a Wavy or Stiff Sweater Hem

A wavy hem usually means the knit stretched during sewing. A stiff hem usually means the fusible web or stitching is holding the fabric too firmly.

For acrylic sweater knits and sweaters made mostly from synthetic fibers, do not rest a hot iron directly on the fabric. Instead, hold the iron about half an inch to 2 inches above the sweater and let the steam relax the knit. Allow each area to dry before moving or stretching it.

If the hem waves after steaming:

Gently reshape it with your hands while it is warm from steam.
Let the sweater lie flat until fully dry.
If the stitching is visibly pulling, remove that section and resew it with slightly looser tension.
If the twin-needle hem feels firm but lies flat, stretch it gently across the hem rather than pulling on one spot.

Check the Hem Before Wearing the Sweater

Before putting the project away, make sure the hem works as well as it looks.

Try the sweater on and raise your arms, sit down, and bend slightly. The hem should move without popping stitches.
Check that the front and back hang at the intended level.
Look for skipped stitches, ripples, or a line of tunneling between twin-needle rows.
Turn the sweater inside out and confirm that all tape edges are enclosed in the folded hem.
Wash the sweater using its normal care method, then lay it flat to dry and reassess the shape.

A successful sweater hem lies flat, keeps its stretch, and does not pull at the side seams.

Frequently Asked Questions

What Is the Best Stitch for a Hand-Sewn Sweater Hem?

A loose slip stitch is usually the best hand stitch because it is discreet and does not create a rigid line across the knit. Catch stitches or herringbone stitches can work when you need more give, but use them lightly so they do not show through a fine sweater. Match the thread or yarn closely and avoid pulling each stitch tight.

How Do You Flatten a Sweater Hem?

Steam the hem rather than pressing it flat. Hold the iron half an inch to 2 inches above the fabric, let the steam relax the knit, then leave the sweater flat until dry. This is especially important for acrylic and other mostly synthetic sweater knits, which can lose their springiness under direct iron pressure.

Is It Possible to Hem Knitwear?

Yes, knitwear can be hemmed by folding and hand sewing the existing edge or by using fusible stabilization and a twin needle for a machine-sewn finish. If you cut the sweater shorter, stabilize the cut line first because an unsupported knit edge can begin to unravel. A cut-and-hem alteration is best when removing the original ribbing is acceptable.

What Is the Bottom Hem of a Sweater Called?

The bottom edge is called the hem. When that edge is made from a stretchy vertical-rib pattern, it is called the ribbed hem, bottom band, or ribbing. The lower back hem is simply the hemline across the back of the sweater.

Can You Hem Sweater Sleeves the Same Way?

Yes, sleeves can be shortened with a folded, sewn hem if you are comfortable losing the original cuff or ribbing. The main difference is that sleeve openings are smaller, so sew slowly and support the knit as it moves through the machine. For ribbed cuffs you want to preserve, folding the cuff inward and hand sewing is often less risky than cutting it off.