In this tutorial, we are going to show you how to enlarge jeans at the waist. You can use this fix to enlarge the hips as well if you need to.
Here I have a pair of jeans that I need to upsize at the waist area. I’ve been using different ways to do it, including adding a denim piece at the center back seam or at the side seams. But I’ve found out that adding elastic is actually the way that works best for a couple of reasons.
First, the elastic stretches. This is useful when you are not sure exactly how much to add to the waistband or the size of the waist changes. Second, black elastic looks somewhat like a decorative element.
While denim fabric pieces could never exactly match the color of the jeans. Therefore, it’s easy to tell that the jeans have been altered. So for quite some time now, this is the way we prefer to enlarge the waist on jeans for our clients.
But, if you would rather use denim to enlarge the waist, you can still follow the steps described here.
Here are the written instructions. You are going to find the video tutorial at the bottom of this post.
To enlarge the jeans at the waist, unpick a bit of the side seams and cut through the waistband
First, we need to detach the waistband from the side seam area so that we can release the side seam stitches. Remove just enough of the stitches so that you are able to release the side seam. You don’t want to break a lot of the stitching here because otherwise you will have to restore it at the end.
Here I have to break two horizontal stitches to release the side seam (image 1).
Then, I am going to remove the topstitching that jeans usually have on the side seam right under the waistband (image 2).
How low you should go depends on what you are trying to achieve. If you need to enlarge the jeans only at the waist, you should go just a couple of inches below the waistband. If the jeans are tight at the hip area as well, you might want to join two pieces of elastic on top of each other to get a wider tape and go lower on the side seam.
In that case, you will need to remove those rivets on the sides of the pockets so that you can sew. You might put new ones later or just leave it like that since it is the small holes left by the rivets are not that easy to notice. Sometimes those holes can go in the side seam so you can’t see them at all. I prefer to put a new set on at the place of the old ones.
I am going to start at the bottom as low as I need to go and work my way all the way up (image 3). Make sure you break an inch more on the topstitching than on the joining seam so that you can work.
Then, I am going to cut straight through the waistband (image 4). I want to cut exactly at the mark of the side seam.
Next, I need to open the joining side seam as well. I try to go approximately ¾ inches or 2 cms higher than the topstitch so that I can sew.
This is how it is supposed to look like (image 5). I am going to clean the remaining threads and do the other side.
Measure how much you need to enlarge the jeans with
Measure in order to be sure that both sides are going to be equal (image 6). I like to put a pin to mark the second side and then break the stitching up from that marking pin.
I have both sides prepared (image 7) and now it’s time to put in the elastic.
Measure and cut a piece of the elastic that equals the difference between your waist and the jeans waist (image 8). Divide it by two - one piece for each side (image 9).
You might want to make them just a bit more narrow than the waist measurements so that the elastic does its job and the waist doesn’t end up to be too wide.
I need to enlarge that waist with 6 inches or 15 cms, which is a lot so my elastic pieces are quite wide. But, I need to alter only at the waist, so I don’t go very low towards the hips.
Next, I need to measure the middle of each elastic piece of elastic (image 10). Draw a V-shape on it, using a piece of chalk. Connect the middle mark at the bottom with both top sides (image 11). It looks like this (image 12).
Then, cut through the lines and come out with two triangular pieces (image 13).
Upsize the jeans with elastic band
Now, let’s attach those pieces to the jeans. Make sure that you are using a needle that is appropriate for jeans and that is going to manage to deal with many layers of thick material.
Then, using the straight stitch, attach one of the pieces to the front of the jeans (image 14).
Start at the top of the waistband, align it nicely and sew down. The side seams would stick out a bit more, because there is seam allowance there and we’ve cut straight through the waistband so there is no seam allowance on it.
If you prefer, pin it prior to sewing. I am going to go ahead and sew it like this (image 15).
I am going to serge at those edges in order to make sure that the seams are going to be more durable as well as that the fabric and elastic won’t unravel (image 16). If you don’t have a serger, use the narrow zigzag stitch or any other overcasting stitch on your sewing machine.
Attach the second piece of elastic to the other front side of the jeans and repeat all the steps up to here.
Then, attach the elastic to the back (image 17). Make sure to align the piece to the jeans precisely and make the seam. Again, pin if you need to in order to make it easier to sew. When you are done with attatching the elastic, it should look like this (image 18).
Check the face side of the jeans to see if you are happy with the results, because this is approximatelly how it is going to look like when done. You might as well try the jeans on for fitting before you topstitch.
I am going to serge at the seam as I did on the front side of the jeans (image 19).
Restore the top stitching seams
The last thing we need to do is top stitch. I’ve picked a matching denim thread and I am going to fold the seam allowance towards the denim fabric and top stitch, starting at the top of the waistband (image 20).
Go a couple of inches below the elastic on the side seam (image 21). Pivot with the needle down and sew all the way up to the end of the waistband on the back side of the jeans. Again, fold the seam allowance towards the jeans and top stitch.
I am going really slow because all those layers of fabric and elastic got very thick. I am careful not to break the needle. Here is how it looks like when done (image 22).
On the last image you can see how the jeans look before and after. I’ve managed to enlarge this waistband with 6 inches or 15 cms without touching the hips. The elastic gives the waistband additional stretching.
If you want to enlarge with less inches, use smaller piece of elastic. If you want to enlarge the hips as well go lower on the side seam, joining two pieces of elastic on top of each other and make sure to use a seam that stretches as well.
Here is the video tutorial on this alteration.
If you want to learn how to make all of the most common alterations on ready to wear clothing, here is a great online course on Tailoring Ready-to-Wear.
Some more recources on jeans alterations:
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