Tutorial-Add An Adjustable Waist to Any Pants

Let’s face it.  Most kids have no butt and no hips, their waist just goes straight down to their legs with nothing to hold the pants up.

Notice gaping in the back

I could never get my children to wear a belt.  I think that it was too difficult for them to unbuckle & buckle for bathroom breaks when they were younger.  If I was lucky I would find the more expensive pants, jeans and slacks that come with that nifty button and tape arrangement so I could adjust the size of the waistline.   Notice the operative word there is “expensive”.

So what to do if you can’t find the pants you want with an adjustable waist?  Or you are using hand me downs and thrift store pants? Never fear~there is a frugal retrofit option!

In this tutorial I’ll show you a quick and easy way to fix the problem~you don’t even need to know how to sew.  All you need is a nifty product called Buttonhole Elastic and you can add your own adjustable waistline to any pair of pants.

3/4 inch Button Hole Elastic

The holes are prespaced & cut.

I was not able to find buttonhole elastic in my local fabric and craft stores.  That left me with two options.

1.  Using your sewing machine and buttonhole foot, sew your own buttonholes into regular elastic tape.  Note:  Do not just cut slits, they will unravel the elastic.  You need a sewn buttonhole.

2.  Purchase buttonhole elastic online.

I went with option 2.  An internet search turned up both elastic by the foot and in 30 yrd spools.  Make sure you comparison shop-3/4″ buttonhole elastic spools ran anywhere from $52 to $14.  For the same exact thing.  With shipping etc I spent about $20-but that should do about 30 pairs of kids pants.  I also let my friends know I have the elastic and that I’d be willing to sell them a yrd at a time at my cost.

Now on to the tutorial!

Altering Pants to Add An

Adjustable Waist


Missing item: Fray Check

Buttonhole elastic
2 buttons
needle & thread
Seam Ripper
Safety Pin
Optional but recommended: Fray Check


1.  Check to ensure that your waistband is not sewn through anywhere along it’s length.  It should be a casing or tube all the way around that you can feed the elastic through.  99.9% of pants are constructed this way.  If yours aren’t~well, you are stuck & can’t use this technique.

See-the waistband is really a tube!

2.  Carefully use the seam ripper to cut a slit about 1 1/2″ to 2″ to either side of the zipper on the INSIDE of the waistband.  Do not cut through any stitching.

Cut carefully-you can't undo this!

3.  Sew a button directly in front of the slit (closest to the zipper opening) on the inside of the waistband.  Choose a button that fits easily in the slot of your buttonhole elastic.  The color doesn’t matter-no one will see it.  Take extra care that you do not sew all the way through the waistband-you don’t want to see the stitching on the outside.  I slid my scissors into the slit (closed) to make sure I didn’t accidentally sew all the way through.

Finished slit


4.  Cut a piece of buttonhole elastic that just fits comfortably, without stretching, around the waist of the person who will be wearing the pants.

5.  Finish both ends of the elastic so it doesn’t unravel.  You can either fold over a very small piece and sew it down or you can just use Fray Check.  I did neither on my first pair of pants and after 3 or 4 washings the elastic unraveled and I had to use a new piece.  Learn from my mistake!

6.  Slip the elastic over one of the buttons.  Then attach a safety pin to the unsecured side.  Make sure the pin is a size that will fit easily through the waistband casing.

All ready to go.

7.  Thread the elastic through the waistband casing & secure on the far button.

All threaded through. I adjusted the tape later so it was centered.

8.  Wear and enjoy!

Much better.

I’ve fixed quite a few pairs of pants for the kids this way.  I’m even considering using the technique on some of my jeans that ALWAYS gap at the back, even though they fit perfectly everywhere else.

Good luck and happy altering!

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  1. Sarah Caz says

    Another option is to use Dapper Snappers. This way, you don’t have to cut or sew anything and it can be used on all your pants.

    • Jenn @ Frugal Upstate says

      Sarah-I had never seen the dapper snapper before-that looks like a great option for small children. However my 4th grader (who is the one shown in the pictures) would not wear something like that-far too uncool. In her case the hidden button tape is the best bet :)

  2. says

    The picture of your pincushion made me smile – it looks just like mine with the whole assortment of different size pins all stuck in there! Thanks for sharing this helpful tip, and the pincushion picture :)

  3. Teresa says

    I often do this with regular elastic. I just cut slits in it for the buttonholes. It works really well and has held up for years.

  4. krista says

    how wonderful!!!!! my daughter and neice always have this problem with their pants!! actually when i was in high school i had this problem too and had to put sewing darts in my pants but this would have been nice!!

  5. Deb Killenbeck says

    I am sewing some easy on elastic waist outfits for my 95 year old aunt. I wanted to use the button hole elastic to make them adjustable, but could not find any in my area. So I cut two 4 inch strips of ultra suede the width of the elastic. I cut slits in the ultra suede for the button holes and securely stitched the strips onto the ends of the elastic. Viola! Button hole elastic! The ultra suede doesn’t tear, so no need to button hole stitch or bind the slits. Plus it is soft and more gentle against her skin than the elastic.

  6. Roxie says

    I have done something like this for years with pants for kids. EXCEPT I do not bother with the button hole elastic. I just add elastic to the back of the pants and sew it in place on the sides. I take the side seam apart; slip in the elastic, and resew the side seam.

  7. Chris says

    I had never heard of buttonhole elastic or dapper snappers (too bad those go on the outside). Unless they have elastic in the waist, every pair of pants I try on gaps in the back. I have one pair in the back of the closet that I mail-ordered and couldn’t return (dumb dumb dumb). Thank you so much, I can’t wait to try this! Amazon has the BH elastic.

    • says

      Chris-so glad to have introduced you to something that will help you out! Just make sure to either use fray check or else turn a small hem under and stitch down the cut ends of the elastic. Otherwise it WILL unravel (as one pair did for Princess when I was lazy and just left it)

  8. Bre says

    THANK YOU! I have a child with sensory processing disorder and he HATES belts! I have an older son who’s clothes I pass down, but some don’t have the elastic waist. This is perfect! Thank you for saving me about 300 hundred dollars a yr on new pants for him!!!

    • says

      Bre-I’m so glad that this will help you! Just remember to do something with the ends of the elastic so it doesn’t unravel-my first ones came all apart and then the subsequent ones where I just folded over a bit and stitched it down or used fray check did fine!

  9. Melissa says

    This is a wonderful tip, Thank You for sharing! I am losing weight (inches at the moment) your idea is a terrific alternative to pinning my pants waists. It will also permit me to keep wearing my favorite slacks and skirts until I’ve lost enough inches in my waist line to purchase smaller slacks.

    • says

      Well, since the elastic waistband that is currently in the pants is in a casing all the way around, I would think that you could carefully cut the slits and side the elastic through. I don’t think I’d want to remove the elastic that was already inside–it might make the front lay strangely.

  10. Susan says

    Thanks, this is exactly what I was looking for! My 2 year old is super tall and thin and all the new children’s pants only come with decorative drawstrings so this means he’ll finally be able to fit pants that aren’t too short!

    • says

      Jessica–I haven’t had it fray in the kid’s pants, but it would depend on the type of fabric and how long they are in use. My kiddos tended to grow out of things fairly quickly when they were at an age to need this. If you were concerned you could try using a little fray check to seal the edges of the cut–although you’d have to be careful not to glue the whole thing shut accidentally! Maybe slide a little piece of wax paper or something in and do it one side at a time? Another option would be to take a needle and thread and do a blanket stitch around the edges–basically as if you were doing a hand sewn button hole. This tutorial seems to show it fairly well:

  11. Kathy says

    This is AWESOME!! Thank You for sharing! My 7 yr old’s waist is small, but his legs are long so I always need to buy shorts & pants with adjustable waistbands (which are more expensive & hard to find). I ordered some uniform shorts online not realizing that they had the flex waist at the back… which doesn’t help him. I would need to order 2-3 sizes smaller… but then they would be too short! I will be able to cinch the waist on the sides now and not have to hold on to them for years before they fit him! Again, THANK YOU so much!!


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