Polyester can be stretchy or non-stretchy depending on how the fabric is made. As a general rule, knitted polyester fabrics are the most stretchy (eg. t-shirts), woven polyester fabrics basically have no stretch (eg. flowy blouses), and woven polyester fabrics with elastic fibers have some stretch (eg. work pants).
I explain this further below with real fabric samples and clothes, and describe the common exceptions to these rules.
What do you mean by “woven” vs “knitted” polyester?
Fabric is “fiber + how the fibers are joined together”. Polyester is a “fiber” – thin “threads” made from crude oil chemicals (mostly). Fibers are then joined together to create fabric, mainly by weaving, knitting, or felting them together. This affects whether the final fabric is stretchy.
The threads are joined together by weaving them on a loom machine. The most common type of weave is the “plain weave” where each thread is in a simple grid pattern, going above and under each thread. Woven fabrics generally don’t stretch. There are 3 main exceptions.
First, if the fabric is cut on the “bias grain” (at a diagonal angle) it will have some stretch. This is done to create slinky and drapey polyester slip and cowl-neck dresses, for example, where the fabric shouldn’t be stiff.
The other exception is if elastic fibers are mixed into the fabric (like elastane, lycra, or spandex). These fibers are tiny rubber tubes that give the fabric good stretch and recovery, allowing the fabric to bounce back to its original shape after being stretched (or at least mostly). You’ll see this in jeggings that are made from polyester and elastane.
Thirdly, if the fabric is woven using certain techniques or heat-set, like puckered crepe or crinkled “crepon” textures, they’ll have a little “give”, but they’re not that stretchy.
The fibers can be knitted together to create a structure of interlinked loops. This loop structure gives the fabric “mechanical stretch”. Polyester jersey is an example of a knitted fabric often used in loungewear and activewear.
The fibers can be felted together to create “non-woven” materials like felt.
How do you know if your fabric is woven or knitted?
Look at the fabric closely and see how the threads are arranged. As a general rule of thumb, here’s what to look for as a beginner:
- Are the threads joined together in rows of small loops? Then the fabric was knitted.
- Are the threads in a grid-like structure, with threads overlapping each other at right angles? It’s a woven fabric.
Now let’s see some real fabric samples and clothes to help you understand this better. Let’s see which ones you can guess right 🙂
Sample 1: Flowy plain-weave polyester fabric = no stretch
This is a common fabric that you’ll see in flowy tops and dresses. It’s a normal plain-weave woven fabric. Because of this construction method, the fabric does not have any stretch from left-to-right or top-to-bottom. You’ll only feel a bit of stretch if you pull the fabric along the “bias grain” (at a diagonal angle), but generally, clothing is not cut along the less stable bias grain, so you won’t feel this stretch when wearing the garment.
Sample 2: Thin polyester chiffon = no stretch
This is a woven fabric that’s lightweight, smooth, and see-through. It doesn’t stretch (except when pulled at a diagonal angle along the “bias grain”).
Sample 3: Polyester georgette = no stretch
This looks similar to chiffon but is thicker and less see-through. It’s also a woven fabric. It doesn’t stretch (unless it’s pulled at a diagonal angle along the “bias grain”).
Sample 4: polyester-cotton shirt = no stretch
This fabric is made from a mix of polyester and cotton fibers, but they’re woven together and have no elastic fibers, so the fabric has no stretch. You’ll see this type of fabric often in office and school shirts. (The exception with all woven fabrics is that they’ll stretch a bit when pulled at a diagonal angle along the “bias grain”, but unless your clothing is cut along this grain, you won’t feel any stretch when wearing the garment).
Sample 5: Polyester satin = no stretch unless it’s cut on the “bias”
Satin fabrics are shiny on the front and dull at the back. They’re woven fabrics made using a “satin weave” where long threads are uninterrupted so they reflect light. They generally aren’t stretchy. I have seen exceptions though. Slinky slip dresses and cowl-neck dresses are often made using satin fabrics. The dress pieces are sometimes cut along the diagonal of the fabric (the “bias” grainline), where woven fabrics do have some stretch. By cutting the fabric this way they make the whole dress a little bit stretchy (not much) so it creates drapey styles that hang and “stick” to the body.
Sample 6: Flowy polyester crepe fabric = very small amount of “give”
Crepe is a woven fabric with a crinkled texture. When you stretch it, it has a little “give” (we’re talking millimeters), but it’s not much. This fabric is woven and sometimes heat-set in a way that creates this textured effect.
Sample 7: Polyester fleece = some stretch
A dense, fluffy, and warm fabric used in outdoor fleeces and jackets. It’s knitted together so it has some stretch from left to right, but not always a lot.
Sample 8: Polyester-elastane pants / trousers = stretchy
You’ll often see fitted pants made from polyester fibers with less than 10% elastane. This is a woven fabric, so it doesn’t have any stretch from its construction, but it does have elastane which is a stretchy fiber. So the pants now have some stretch to allow you to move comfortably in fitted pants. You’ll often see fabric like this used for formal pants for office and school wear.
Sample 9: Polyester mesh (eg. Airtex) = very stretchy
This is a knitted fabric with small oval holes. You’ll see it in sportswear tops. Due to its knitted construction, it’s very stretchy (always from left to right, but not always from top to bottom).
Sample 10: Polyester jersey = very stretchy
Jersey is always a knit construction and therefore stretchy. If elastane, lycra, or Spandex fibers are added, the jersey will be more stretchy and have better recovery (meaning it will bounce back to its original shape after being stretched, or at least mostly). Polyester jersey is often stretchy in all directions, but especially from left-to-right. You’ll see polyester jersey in light to medium weight stretchy tops and bottoms for loungewear and exercise, and for slinky and stretchy dresses.
Sample 11: Thick polyester “ponte” knit = very stretchy
You’ll sometimes see “ponte” dresses, leggings, and loungewear pants sold during winter. These are knit fabrics. The knit construction means they’re stretchy, perfect for fitted clothes. Elastane, spandex, or lycra is often added to make it stretchier and improve recovery (“bounce-back” ability). Ponte fabrics are thick and quite structured (meaning they stand away from the body rather than cling to it). Sometimes rayon or viscose fibers are added to make the fabric drapier and softer.
Does polyester stretch out?
If a stretchy polyester “knit” fabric, like jersey, does not have any elastane, lycra, or Spandex content, then it could become stretched out and baggy after being worn. Elastane (and its brand name versions) is a stretchy fiber – lots of tiny tubes of rubber are woven or knitted into the fabric – they help the fabric spring back to its original shape after being stretched. Without it, many “knit”-construction fabrics fail to go back to their original shape.
How stretchy is polyester?
It depends on how the polyester fiber is made into fabric. If it’s woven into fabric then it has no stretch (exceptions exist). If it’s knitted into fabric then it could stretch anywhere from 1% to 100% of its original size. Polyester-elastane jersey is a good example of a very stretchy fabric.
Are polyester-blend fabrics stretchy?
If the polyester is blended with elastane, lycra, or Spandex fibers, then yes it will have some stretch. Otherwise the structure of the fabric (knit vs woven) is a more important factor. Other blends of fibers (like viscose, cotton, or acrylic) will generally affect other properties of the fabric (drape, breathability, etc), but will have no effect on the stretchiness of the fabric.
Is polyester stretchy in jeans?
Normal jeans that are thick and a bit stiff with a few percent of elastane, spandex, or lycra will often have some stretch so you can move comfortably in your jeans. 3-7% elastane content is common. Tight jeggings (“jean-leggings”) will normally be made using a knitted construction and have stretchy elastic fibers inside making them very stretchy.