How to Alter a Sweater That Is Too Long or Small (Easy Tips)

T-shirts and shirts are all easy enough to alter, but what about sweaters? With most off-the-hanger options seeming to cater to the type of ‘average’ body that, in reality, is anything but average, there’s certainly a call for it… but is it possible?

Is it possible to alter a sweater? Some people say no. But don’t believe them. If your sweater’s too big, too small, too long or too wide, you’re not stuck with it.

Providing you know your way around a sewing machine (or can at least thread a needle), you won’t have too many problems in making some basic alterations at home.

How to Take in a Sweater That is Too Big


If your sweater’s several sizes bigger than you are, don’t despair. Depending on just how much time you have on your hands (or just how much effort you’re willing to put in), you’ll find any number of temporary and permanent ways of altering its size… take these two methods as a case in point.

Method 1 – The Boil Wash - Take a look at the care instructions on the sweater’s label. Then ignore them. If you’re going to try the boil wash method of shrinking an oversized sweater, you’re going to have to forget everything you’ve ever been taught about proper care techniques.

The method is simple enough: simply pop the sweater in the washer, wash on the highest heat you can, then dry it on a high heat in the dryer. Try it on for size. If it fits, great. If it’s still on the large side, put it through another wash/ dry cycle.

Just bear in mind that some fabrics don’t take kindly to this kind of treatment, so don’t risk it on a particularly precious garment. If it’s a regular wool or cotton sweater, on the other hand, you’ll find subjecting it to a high heat the easiest and simplest way to shrink it.

Method 2- Sew it Smaller - If you can thread a needle, you’ll find this simple method of taking in a sweater a breeze. Start by measuring how much you need to take the sweater in by (it may help to find a well-fitting sweater and use that as a template). Flip the sweater inside out and mark the areas you need to take in using a fabric pen. Sew a new seam using the mark as your guide. Cut away any excess fabric, flip the sweater right side out, and voila – job done!

Altering a Sweater That is Too Wide


If your sweater’s too wide, don’t relegate it to the back of the closet just yet. If you’ve got a serger, you can simply narrow the sweater by serging it smaller.

If you don’t have a serger (and don’t want to invest in one), it’s still simple enough to narrow a sweater with the right cutting, pinning, and sewing technique. All you’ll need is a little courage, a pair of scissors, a handful of pins, and a needle.

  • Step 1 - Start by lopping off the sleeves at the seam.
  • Step 2 - Pin the sweater to fit. Using the pins as your guide, sew a new seam along the lengths. Remove the seams from the sleeves, then pin to fit and sew.
  • Step 3 - Pin the sleeves back to the sweater, right sides together, and sew to finish.

How to Alter a Sweater That is Too Long

A hip-length sweater is fine. One that’s grazing your knees might need a little help. Give it a fighting chance to reclaim its place in your closet with this easy hemming method.

  • Step 1 - Cut away the original hem of the sweater, then try on the sweater for size. Measure how much needs to be removed, then pin to the required length (if you can, grab a friend for this part).
  • Step 2 - Take the sweater off and flip inside out. Using a fabric pin, mark a dotted line all around the circumference of the sweater to indicate where the new hem should sit. Remove the pins.
  • Step 3 - Fold the hem of the sweater up to the dotted line. Iron the fold in place.
  • Step 4 - Measure from the edge of the sweater to the crease of the fold. As this measurement determines how thick the bottom edge will be, trim a few centimeters off the bottom edge if you’d like a thinner edge.
  • Step 5 - Sew a straight line of stitches around the circumference of the edge to stop it unraveling. Fold the hem to the crease, then use a capstitch to sew along the hem edge. Tie the threads at the side seams of the sweater to close.

How to Alter a Sweater That is Too Small

If your sweater’s a little too snug for comfort, stretching it to fit should be easy enough if it’s made from a knitted fabric.

  • Step 1 - Wash the sweater in cold water. While it’s still wet, wrap it in a towel and towel dry to remove any excess water – you want it to be damp but not soaking.
  • Step 2 - Lay a dry towel over a flat surface. Place the sweater on top and gently pull it into the right shape.
  • Step 3 - Working your way along the sides of the sweater, gently pull it out to the desired size.
  • Step 4 - Pin the sweater to the towel (this will stop it snapping back to its original size) and leave it to air dry. Done correctly, this method will let you increase the sweater by a full dress size – don’t be tempted to size it up by any more than this, or you risk it becoming misshapen.

How to Shorten Sweater Sleeves

If you’re tired of constantly hiking up dangling sleeves, tackle the problem once and for all with the quick sleeve-shortening method.

  • Step 1 - Gather your tools. You’re going to need a perfectly fitting sweater, a twin needle, and some wooly nylon thread.
  • Step 2 - Place the perfectly fitting sweater on top of the not so perfectly fitting sweater. With a fabric pen, mark the sleeves of the sweater you’re altering around 1/2inch further down from where the sleeves of the good sweater end.
  • Step 3 - Cut the sleeves at the mark. Fold the sleeves in by ½ inch and iron the crease in place.
  • Step 4 - To finish, hem the sleeves by sewing a line of straight stitches about ¼ inch up from the edge.

How to Alter a Sweater Neckline

How-to-Alter a-Sweater-Neckline

If your sweater’s neckline is letting it down, a few small alterations should soon bring it up to par. First of all, work out whether you want to add to a too-low neckline or make a too-high neckline lower, then choose the appropriate altering technique from below.

Adding to a Sweater Neckline

  • Step 1 - Cut out a piece of elastic material in a similar color and material to your sweater. It should measure double the circumference of the neckline of your sweater and ½ inch wider than how much you want to add to the collar. Cut the material in half lengthwise.
  • Step 2 - Fold the pieces of fabric ¼ inch in on both sides to stop it unraveling. Pin, then sew to secure.
  • Step 3 - Flip the sweater inside out and place it on a flat surface. Line up one half of your fabric with the front neckline and pin in place. Do the same with the second piece of fabric at the back of the sweater.
  • Step 4 - Sew your neckline in place, attaching both ends of the fabric together to form a continuous collar.

Reducing The Neckline

  • Step 1 - Flip the sweatshirt inside out and draw in a new neckline around 1 inch above where you want the collar to eventually sit.
  • Step 2 - Remove the seam along the neck and separate the shoulder seams to end around 1 inch below the neckline you’ve drawn. Cut the fabric along the new neckline and measure the front and back of the line.
  • Step 3 - Cut a piece of semi-elastic fabric to the length of the front and back of the neckline and with a width of around 2.5 inches. Fold the fabric ¼ inch on either side and sew to secure.
  • Step 4 - Line up the elastic fabric with the neckline of your sweatshirt so the seams face inwards. Fold 1 inch of the sweatshirt’s neckline back so 1 inch of the elastic fabric is visible at both the front and back of the neckline. Sew along the bottom of the fabric line to secure in place. To finish, resew the shoulder seams.

Alter a Turtleneck Sweater


If you want to give your old turtleneck sweater a brand-new look, try this simple method of re-fashioning it into a crew neck.

  • Step 1 - Flip the sweater inside out. Snip the threads joining the turtleneck to the sweater and pull away the yarn. The turtleneck should now be separate to the sweater – if you’re happy with how the raw edge looks, you’re fine to stop here. If you’d prefer a neater finish, proceed to step 2.
  • Step 2 - Roll a small amount of the neckline inside the sweater and pin in place. Hand sew the rolled edge to the inside of the sweater to give a clean finish to your new neckline.

Alter knitted Sweater

Altering a knit sweater can seem an intimidating task, but providing you know how to operate a pair of scissors, it’s easier than it seems. You will, however, need to step carefully – get to scissor happy and that’s the end of your sweater. The process of cutting a sweater to make alterations is known as ‘steeking’ – here’s how to do it.

  • Step 1 - Mark out the area you want to cut (or steek) with pins.
  • Step 2 - Sew a line of short stitches around the area to be steeked to stop the knit unraveling.
  • Step 3 - Cut away the area to be removed, taking care not to cross the stitched boundary. Finish by rubbing together the edges of the cut sections to help them stick together or ‘felt’.

Alter Wool Sweaters


Wool sweaters can be altered using the same method of ‘steeking’ as described in the previous section. Some of the alterations that can be made to a wool sweater include:

Shortening: Cutting a sweater’s hem can be done easily, instantly transforming a too-long garment into a more desirable length.

Neckline: Cutting into the neckline of a wool sweater can transform a turtleneck into a crew neck, or a crew neck into a boat or v-neck.

Style: If you’ve got a wool sweater but would really prefer a cardigan, you can easily change the style by cutting straight up its middle.

Can You Alter a Cashmere Sweater?

Making alterations to an expensive fabric like cashmere can be a little nerve-wracking. But it needn’t be. Adjusting a cashmere sweater is really no different from adjusting any other kind of knit– although you’re likely to be a lot more upset with yourself if you slip up with the scissors. Take it slow, take it steady, and don’t get too carried away as you cut.

  • Step 1 - Flip the sweater inside out and mark where it needs to be taking in with pins. Take the sweater off and use a fabric marker to mark the alterations.
  • Step 2 - Cut away the excess fabric, taking care to remove from the outside of the marked lines only. Work on one seam line at a time to stop any chance of the cashmere unraveling.
  • Step 3 - Seal the cut edges of the fabric on your sewing machine using a narrow zigzag stitch. Let the fabric glide through the machine – pulling it make cause the unfinished edges to rip.​
  • Step 4 - Using a stretch stitch, sew the cut pieces together. For the raw hems and sleeves, you can either use a zigzag stich and let the edges roll or, if you’d rather a cleaner finish, fold, press, and hem them.

By now, you should know how to alter a sweater six ways to Sunday. If you know of anyone else in need of some handy tips, please feel free to share the post.

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