The three ways to attach elastic to fabric
You can sew elastic into fabric in three ways: by stitching it directly to the fabric edge (called direct process), by folding the fabric over the elastic and stitching a casing, or by sandwiching the elastic between two layers of fabric. Which method you use depends on where the elastic goes, how much stretch you need, and whether you want the elastic to show or hide.
Direct process is fastest and works for waistbands, cuffs, and armholes where the elastic will be on the inside. A casing hides the elastic completely inside a fold of fabric—common in drawstring waistbands and the tops of pajama pants. Sandwiching works when you want the elastic hidden but don't have room to fold a casing, like on a fitted neckline.
All three methods use a sewing machine and basic supplies you likely already have. The main difference is how you prepare the fabric before the elastic goes in.
Key Takeaways
- Direct process means stitching elastic flat against the fabric edge with a zigzag stitch, and works best on waistbands and cuffs where the elastic will be hidden inside.
- A casing is a fold of fabric that wraps around the elastic, hiding it completely, and requires you to leave a small opening to thread the elastic through.
- Sandwiching places elastic between two layers of fabric and stitches them together, which hides the elastic without needing a fold or opening.
- Measure your elastic to fit snugly around the body part—it should stretch slightly when you put it on, not hang loose or cut off circulation.
- A zigzag stitch prevents the elastic from breaking when it stretches, while a straight stitch will snap under tension.
Direct process: stitching elastic flat to the fabric edge
Direct process is the simplest method and the one most home sewers use first. You pin the elastic to the wrong side (inside) of the fabric edge, then stitch it down with a zigzag stitch. The elastic stays flat against the fabric, and the seam allowance folds over it when you finish the garment.
Start by cutting your elastic to the length you need—measure it around the body part (waist, wrist, ankle) and subtract about half an inch so it pulls slightly when worn. Pin one end of the elastic to one end of the fabric edge, then pin the other end to the other end of the fabric. The elastic will be shorter than the fabric, so it bunches up between the pins.
Divide the elastic and fabric into quarters and pin at each quarter mark. This spreads the bunching evenly. Set your machine to a zigzag stitch (width 2 to 3, length 2 to 2.5) and stitch along the edge, stretching the elastic gently as you sew so it lies flat. The zigzag stitch flexes when the elastic stretches, so it won't snap.
Once the elastic is stitched, fold the seam allowance over it and stitch again with a straight stitch to encase it. This hides the raw edges and locks the elastic in place. The elastic is now on the inside of the finished garment.
Making a casing: the hidden-elastic method
A casing is a tunnel of fabric that wraps around the elastic. It hides the elastic completely and is the standard way to finish drawstring waistbands and the elastic tops of pajama pants. The trade-off is that you need to leave a small opening to thread the elastic through.
Fold the fabric edge down toward the inside of the garment by the width of your elastic plus a quarter inch. Press the fold flat with an iron. Then fold it down again by the same amount and press again. You now have a double fold that creates a tunnel. Pin this fold in place.
Stitch close to the inner fold (the fold closest to the body of the garment) with a straight stitch, but leave a 1.5-inch opening. Backstitch at the beginning and end of the opening so the stitches don't unravel. The opening is where you'll thread the elastic through.
Cut your elastic to length (measure around the body part and subtract half an inch). Attach a safety pin to one end of the elastic and thread it through the opening, working the pin through the casing tunnel. Once the elastic is all the way through, overlap the ends by half an inch and stitch them together with a zigzag stitch. Tuck the joined elastic back into the casing and stitch the opening closed with a straight stitch.
Sandwiching: elastic between two fabric layers
Sandwiching works when you want the elastic hidden but don't have room to fold a casing—for example, on a fitted neckline or armhole. You place the elastic between two pieces of fabric and stitch them together, trapping the elastic inside.
Cut a strip of fabric (called a binding) that is twice the width of your elastic plus half an inch for seam allowances. The length should be the measurement around the body part plus half an inch for overlap. Fold the binding in half lengthwise with wrong sides together and press it flat.
Open the binding back up. Place the elastic along the center crease, then fold the binding back over it so the elastic is sandwiched inside. Pin the binding to the garment edge with the elastic facing inward. Stitch through all layers with a zigzag stitch, stretching the elastic gently as you sew so it lies flat.
Fold the binding to the inside of the garment and stitch it down again with a straight stitch, close to the inner fold. The elastic is now completely hidden between the two layers of binding fabric.
Choosing the right elastic width and stretch
Elastic comes in different widths—quarter-inch, half-inch, one-inch, and wider. Narrower elastic works for cuffs and necklines; wider elastic is better for waistbands because it distributes pressure over a larger area and is less likely to roll or twist.
Elastic also comes in different stretch amounts. Standard elastic stretches to about two times its resting length. Power elastic (sometimes called swimwear elastic) stretches less and recovers faster, so it holds its shape longer. Braided elastic is flat and doesn't roll; cord elastic is round and can twist inside a casing.
For a first project, quarter-inch or half-inch standard elastic is the easiest to work with. Measure it around the body part where it will sit, then subtract half an inch to one inch depending on how snug you want it. The elastic should feel snug but not tight enough to cut off circulation.
Common mistakes and how to avoid them
The most common mistake is using a straight stitch instead of a zigzag stitch. A straight stitch is rigid and will snap when the elastic stretches. Always use a zigzag stitch when stitching elastic directly to fabric.
The second mistake is cutting the elastic too long. If the elastic is the same length as the fabric or longer, it won't pull the fabric in and the garment will be loose. Subtract at least half an inch from the body measurement so the elastic has to stretch to fit.
The third mistake is not stretching the elastic evenly as you sew. If you bunch it all in one spot, that area will pull tighter than the rest. Pin at quarter marks and stretch gently and steadily as you stitch.
Finally, don't skip the pressing step when making a casing. A pressed fold is easier to stitch straight and looks more professional. Use medium heat and press from the wrong side of the fabric.
Measuring and cutting elastic the right way
Measure the elastic around the body part where it will sit—waist, wrist, ankle, or chest. Use a soft measuring tape and measure snugly but not tight. Write down this number.
Subtract half an inch to one inch from this number, depending on how much stretch you want. For a waistband, subtract three-quarters of an inch. For a cuff or neckline, subtract half an inch. This gives you the length to cut.
Cut the elastic straight across with sharp scissors. If the cut is jagged, the elastic will fray and be harder to thread through a casing. Mark the length on the elastic with a pen before you cut so you don't accidentally cut it too short.
If you're making a casing and need to join two pieces of elastic, overlap them by half an inch and stitch them together with a zigzag stitch before threading them through the casing. This creates a smooth join that won't catch on the fabric.
Frequently Asked Questions
What stitch should I use to sew elastic?
Use a zigzag stitch when stitching elastic directly to fabric. A zigzag stitch flexes and stretches with the elastic, so it won't snap. Use a straight stitch only after the elastic is already attached, to finish the seam or close an opening.
Can I sew elastic with a straight stitch?
No. A straight stitch is rigid and will break when the elastic stretches. The only exception is stitching the ends of elastic together before threading it through a casing, where there is no stretching. Always use a zigzag stitch for direct process.
How tight should elastic be?
The elastic should feel snug when you put it on but not tight enough to cut off circulation or leave marks on your skin. A good test is to slip one finger under the elastic—you should be able to move it slightly but not pull it away from the body.
What do I do if my elastic is too loose?
If the elastic is too loose after you've sewn it in, you can overlap the ends and stitch them closer together to make it shorter. Open the casing or seam, remove a small section of elastic, overlap the ends more, and stitch them together again. Then close the seam back up.
Can I use elastic on stretchy fabric like spandex?
Yes, but use a narrower elastic (quarter-inch or half-inch) and a shorter length. Stretchy fabrics already have give, so you don't need as much elastic. Test the fit before you sew it permanently. You may also want to use a ballpoint needle designed for knits so you don't skip stitches.