A sewing tutorial for how to sew jeans waist smaller with buttonhole elastic.

One of my tween-aged kids has outgrown the kids section for pants in length, but the juniors length waist is way too big. I know this isn’t a terribly unique problem, but retailers do not seem to have made any adjustments. Leggings are no longer desirable, so I set to experimenting with thrifted pants recently. Buttonhold elastic was easier to install than I expected and they’re thrilled to have jeans that fit! I’m sharing a tutorial for how to alter pants waists smaller, just keep scrolling!

This tutorial assumes that you’ve found pants with a simple, flat waistband that doesn’t have any elastic already encased. The waistband pictured above had existing elastic and multiple rows of stitching – while it would be possible to deconstruct it all and add the buttonhole elastic, it would be very time consuming. So, skip those!

I think that this alteration would work well for postpartum folks, folks with fluctuating weight or bloating, not just kids! It’s pretty subtle and relatively reversible if for some reason you wanted to go back to the original waistline. You’d just have to snip the buttons off and pull the elastic out, with the buttonholes remaining. 

If you like this post, check out these other posts while you’re here!

• How to redesign old jeans – 15 denim refashion ideas
• What to do with old jeans – 45+ upcycle sewing tutorials
• How to make jeans skinnier – overalls refashion
• Sewing tips for beginners -15 mistakes to avoid!
• 20+ Easy beginner sewing projects

Pin this tutorial for how to sew jeans waist smaller with buttonhole elastic with this link or image below:

How to sew jeans waist smaller with buttonhole elastic

Supplies

As always, assume you need an iron, sewing machine, thread, scissors!

• Seam ripper
• Marking pen (I used a chaco pen here)
• Buttonhole elastic – .75″ width is used here
• Buttons- 18 mm size used here
• Fusible interfacing– doesn’t matter a ton what type you use!
• Bodkin (optional- can use a safety pin too)
• Lighter
• Optional/things to consider:
  • a walking foot if you’re working with really thick denim
  • denim needles if you’re working with true denim

Steps

Before you start -I would highly recommend testing your buttonhole function on a similar scrap of fabric – making sure to take note of where the buttonhole process starts so you can follow suit on your waistband.

To be clear, there are multiple ways of doing this; however in this tutorial the elastic is threaded through the waistband as one single piece. The buttonhole elastic is not sewn to anything – only attached to the buttons themselves!

Step 1- Seam ripping time! All pants are constructed differently – on the first pair I worked on, the waistband came completely off when I seam ripped this same area, these pants appear to have a folded over waistband. I chose to seamrip roughly 6 inches on each side of the pants (with the label as the middle, only one side is shown above). You need enough room to comfortably sew the button hole and sew the button on next to it! You can seam rip the entire waistband if you’re so inclined, it just means more sewing back together and can make it trickier to realign everything.

Step 2- Mark your buttonholes! Make sure there is enough space on each side to let the buttonhole foot work smoothly. When you’re marking where the buttonhole goes, take into consideration where the belt loops are and where pocket fabric is (you don’t want anything to get in the way of the needle as you sew..  Make sure you’re starting the buttonhole high up enough that you will be able to sew the waistband back together without sewing over the buttonhole.

Step 3- Trim a small scrap of interfacing and iron it on on the inside of the waistband, underneath your buttonhole marking. This helps stabilize it!

Step 4- Sew your buttonholes where you’ve marked! Double check both sides to make sure it all looks nice and neat before seam ripping to open the buttonhole, trim threads.

Step 5- Double check that your elastic fits through smoothly before you sew everything back together! You could, in theory, make it wider if need be.

Step 6- Hand sew the buttons on, between the buttonhole and the front of the pants. I aimed for roughly 1 inch away from the opening, but it doesn’t have to be exact.

Step 7- Cut a piece of elastic off! I loosely marked off the length from button to button, unstretched, and then removed 2 inches (it gets smaller again when you sew the edges over). It’s better to have too long of elastic than too short, since it’s easy to cinch up! Sew each elastic end over and then use a lighter to burn and seal the edges. You can just burn the edges but it felt slightly rough to my hand so I decided to err on the side of comfort.

Step 8- Carefully resew your waistband back together along the original stitching line, making sure that the interior raw edge is staying folded down. You could absolutely pin or even glue stick this all if you feel like you need to – I felt like it was all really sturdy and did not.

Step 9- Attach the elastic on one button. Then take the loose end in your bodkin and thread the elastic through, going slowly to avoid twisting. Make sure that the burned edge is facing in, towards the fabric, on both sides. 

If you want to, you can fold the excess elastic and button it through a second time for a nice loop instead of a floppy end! You’re done!