How to Sew Stretchy Fabric: My Best Tips for Successful Sewing

Sewing with stretchy knit fabrics can be tricky for beginners. I have been sewing knits successfully for more than 10 years now, but when I started I made quite a few common mistakes. In this post I have gathered my best tips to help you to avoid the usual pitfalls, and learn how to sew stretchy fabric successfully right from the start!

We will go over the following topics:

• Choosing the right fabric for your project
• Essential and helpful tools
• Settings for your sewing machine
• Stitch options
• How to hem stretchy fabric
• Do you need a serger for sewing stretchy fabric?

So let's get started!

Choosing the Right Fabric for Your Project

Selecting the right stretch knit fabric is key to ensuring your sewing project fits properly and achieves the intended style. Knit fabrics vary in amounts of stretch, recovery, and drape/structure, so understanding these properties will help you evaluate your fabric and choose the right one for your project. When shopping for fabric online, most shops will include many of these descriptors in their listings.

Key factors to consider when choosing your fabric

• Stretch percentage: How far the fabric stretches (e.g., 30% or 50%). Check out our free printable stretch measurement ruler. Most knit patterns for will list a minimum recommended stretch percentage, in order to achieve the drafted fit.
• Stretch type:
  • Two-way stretch: Stretches in one direction (usually across the grain).
  • Four-way stretch: Stretches both horizontally and vertically (required for activewear and other tight fitting garments).
• Recovery: Does the fabric return to its original shape after being stretched? Stretch recovery is very important in fitted garments - fabric with poor recovery will end up stretched out and baggy.
• Spandex content: Fabrics with spandex (also known as Lycra/Elastane, which are brand names for spandex) offer better recovery and compression.
• Drape vs. structure:
  • Drapey fabrics like bamboo jersey flow smoothly for dresses and soft tops.
  • Structured fabrics, like French terry, add volume and shape—perfect for hoodies or full skirts.
• Fabric weight: Heavier fabrics provide more structure and work best for pants and skirts that need more thickness. Lighter fabrics are better for flowing designs.

Matching your fabric to your pattern’s recommendations ensures a great fit and style. When in doubt, reach out to the fabric store for advice!

Using the Right Tools for Stretch Fabric

The right tools can make sewing stretchy fabrics much easier. Here are a few essentials that can help:

• Stretch or Jersey Needles: Using the correct needle type is crucial to avoid having skipped stitches. Stretch needles are best for high stretch fabrics with spandex, while jersey/ballpoint needles work well for looser knits like sweater knits.
• Walking Foot or Knit Foot: This attachment helps feed the fabric through evenly, preventing stretching and wavy seams. It’s especially helpful with slippery or bulky knits.
• Wash-Away Tape: If you’re dealing with slippery knits, wash-away tape can stabilize your seams as you sew. It’s especially handy for hems or seams that need to be held in place but still stretch afterward.
• Fusible Interfacing: For areas that need permanent stabilization, such as buttonholes or snap placements, light or heavy fusible interfacing is a great option. It prevents these areas from stretching and popping out of shape.

How to Sew Stretchy Fabric: Sewing Machine Settings

Getting the right settings on your machine is key to achieving smooth, non-wavy seams when sewing with stretchy fabrics. Here’s what to focus on:

• Presser Foot Pressure: Lowering the presser foot pressure can help prevent the fabric from stretching out of shape as it passes through the machine. If your machine allows it, make sure to experiment with this setting.
• Stitch Length: A longer stitch length can help prevent wavy seams. For straight stitches, increasing the length to 3 or more can make a significant difference.
• Tension: While tension adjustments are normally unnecessary for knits, on rare occasions, you may need to lower it slightly for heavier fabrics. Tension problems are often caused by incorrect threading, so try re-threading your machine before adjusting the tension, ensuring that your presser foot is up while threading, and the thread is securely seated between the tension discs.

Pro Tip: If you're still having trouble, especially when hemming, wash-away tape or fusible hem tape can stabilize the fabric while you are sewing.

How to Sew Stretchy Fabric: Choosing the Right Stitch

Not all stitches are created equal when it comes to sewing knits. Stretchy fabrics, such as those with spandex, require stitches that can stretch along with the fabric to prevent popping seams. Here are some of the best options:

Stitches for Seams

• Lightning Bolt Stitch: Available on most modern machines, this stitch is great for a subtle, stretchy seam. However, it may not always hold up to heavy stretching.
• Triple Stretch Stitch: This is my personal favorite for sewing knits. It creates a super stretchy and strong seam that holds up well, even under strain. Although it's a bit more difficult to remove if you make a mistake, its durability makes it worth it.
• Zigzag Stitch: For those with basic machines, a zigzag stitch is a great alternative. Adjusting the width and length of the stitch can minimize its appearance while keeping the seam stretchy.

Stitches for Hemming and Topstitching

• Long Straight Stitch: This can be used for topstitching when you don't need the fabric to stretch, but if the hem or topstitching is accidentally stretched, it may pop a stitch and come undone.
• Triple Stretch Stitch: This stitch resembles a regular straight stitch. If you look quite closely it is thicker than a straight stitch, but in my opinion it looks fine for hemming and topstitching, and it is very strong and stretchy
• Twin Needle Stitch: This mimics the professional finish on storebought clothes, but it can be quite finicky to achieve. Twin needles are prone to tunnelling (where the fabric rise up between the stitching rows) and requires some trial and error adjustment to the sewing machine tension. Watch the hemming video below for tips for a successful twin needle stitch
• Cover Stitch: This can only be done with a Cover Stitch Machine - it cannot be done with a regular home sewing machine.

Pro Tip: Use a stretch thread in your bobbin, such as Maxi-Lock Stretch, to add extra strength and flexibility to your seams.

FAQ: Do I Need a Serger for Stretchy Fabrics?

A serger (also called an overlock machine) is helpful for sewing stretchy fabrics, but it’s not essential. Here’s how it helps and why you don't need a serger to sew stretchy fabric, but might want to consider one if you're sewing them often.

How a Serger Helps with Stretch Fabrics

• Creates stretch-friendly seams: Sergers use inter-looped threads that make seams more elastic, perfect for activewear and knits.
• Prevents fabric from stretching out: The differential feed setting ensures lightweight or stretchy fabrics don’t warp as they pass through the machine.
• Finishes seams neatly and quickly: With built-in cutting blades, a serger trims excess fabric while sewing, creating professional-looking edges.

How a Sewing Machine Can Do the Job Alone (But a Serger Can't)

• A simple and strong stretch stitch such as the triple stitch is adequate for seams, and actually stronger than a serged seam - it's ideal for high stress seam such as a pants crotch, and I often reinforce my serged seams in these areas with a triple stitch.
• Though it is a slower process, a regular sewing machine can functionally finish seams using an overlock stitch or a zig zag stitch.
• Knit fabrics do not fray, so optionally, you may choose not to finish your seams at all.
• Sergers cannot do hemming, topstitching, or other non-seam tasks, so you’ll still need a sewing machine for those.

If you sew stretch fabrics often, a serger can save time and create smoother seams—but it’s not a must-have for every sewist.

How to Sew Stretchy Fabric: Test, Practice, and Play!

One of the best ways to find what works for you is by testing different stitches, machine settings, and tools on scraps of your fabric. Play around with the settings and see what combination gives you the best results. Don’t hesitate to try out new techniques or tools to get the perfect seam for your project.

By following these tips, you’ll be well on your way to sewing stretchy fabrics like a pro. Whether you’re sewing leggings, swimwear, or comfy hoodies and t-shirts, mastering these basics will make your projects much more enjoyable!

Happy sewing!