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Recently, for our podcast series Sew Let’s Talk About It, we received the following question about knit fabrics:
Learning to sew for myself and need a cheat sheet for all the different knit fabric types. I can’t keep up with the abbreviations and names and descriptions and weights and amount of stretch.
Do you have this problem too? It is not uncommon to be overwhelmed with all the fabric types when learning to sew. It can be helpful to have a book handy near your sewing machine, or you can bookmark this post if you need help with knits.
Understanding Knit Fabric for Beginners
When evaluating knits, first try to understand these three key features: weight, stretch percentage, and fiber content. Don't worry if you can't identify every knit fabric by name yet. Once you understand these three characteristics, you'll be able to confidently evaluate almost any knit fabric you come across. All of these things work together and influence each other. Once you understand these three characteristics, you'll have a solid foundation for choosing knit fabrics. From there, you can begin exploring more nuanced concepts like drape, recovery, opacity, and fabric structure. In this post, we will cover the three big ideas you need to understand in order to start with knits.
Fabric Weight
Here at Surge, we will typically give the weight of the fabric in GSM (gram per square meter) and/or oz/yard (ounces per square yard). If these numbers do not stick in your head, you can save this graphic to check what weights are considered light, medium, or heavy.
Fabric weight helps you understand how substantial a fabric may feel and what types of garments it may be best suited for. A lightweight knit might be perfect for a breezy summer tee, while a heavier knit may work better for pants, sweatshirts, or more structured garments.
Weight does not tell the whole story on its own, but it's usually the first thing I look at because it immediately narrows down which projects a fabric is best suited for.
As a general starting point:
Lightweight knits are often best for t-shirts, tanks, layering pieces, and warmer weather garments.
Midweight knits are great for classic t-shirts, casual dresses, lounge pants, and everyday garments.
Heavyweight knits are typically better suited for leggings, joggers, sweatshirts, structured dresses, pants, and jackets.
These are not strict rules, but they are helpful starting points when shopping online.
Fabric Stretch Percentage
The stretch percentage is a precise calculation determined by taking the fabric at rest, stretching it, and measuring how far it stretched. You can then check the recommendation from your pattern to see how much stretch it requires. For example, a swimsuit must stretch a lot, but a loose t-shirt does not need much stretch.
When shopping, do not guess on stretch. Always compare the fabric’s stretch percentage to the amount of stretch recommended by your pattern.
A loose t-shirt may only need a small amount of stretch, while leggings, fitted tops, activewear, and swimwear usually require much more. If a pattern calls for 50% stretch and your fabric only has 20%, the finished garment may feel too tight or may not fit as intended.
Stretch percentage becomes increasingly important as a garment becomes more fitted. The closer a garment sits to your body, the more the fabric needs to stretch—and recover—comfortably.
Fabric Fiber Content
Fiber content tells you what the fabric is made from. This affects how the fabric feels, drapes, breathes, wears, and behaves while sewing.
This is also where fabric names can get confusing. Some terms describe the fiber, while others describe the fabric structure. For example, cotton is a fiber. Jersey is a fabric structure. That's why two fabrics can both be called "jersey" but behave completely differently. A Cotton Spandex Jersey, Modal Jersey, and Polyester Athletic Jersey are all jerseys—they simply use different fibers.
A quick note about rayon, modal, bamboo, cupro, and lyocell: these are all in the regenerated cellulose family. They are not identical fibers, but they often share similar qualities like softness, fluid drape, and a cooler feel against the skin. So if you see Modal Jersey or Bamboo Spandex while shopping, those fabrics may not say “rayon” in the name, but they still belong in that same general family on the chart.
How to Choose a Knit Fabric for a Project
To make it easier to pair fabrics to projects, review the three flow charts above and look at each characteristic of your fabric independently.
When I am shopping for knit fabric, I usually look in this order:
1. Weight
2. Stretch percentage
3. Fiber content
The fabric name comes last, because two fabrics called “jersey” can behave completely differently depending on weight, stretch, and fiber.
Let's pretend we've found this fabric while shopping online (this is our Marsala Modal Spandex Jersey). Here's how I'd evaluate it. This fabric is 250 GSM, which places it in the midweight category. That tells us it has more substance than a very lightweight tee fabric, but it is not as heavy or structured as something like ponte or sweatshirt fleece.
Next, look at the stretch percentage. This fabric has 50% stretch, which gives it enough movement for many t-shirts, casual dresses, and fitted garments, depending on the pattern requirements.
Finally, look at the fiber content. This fabric is 96% modal and 4% spandex. Modal falls into the regenerated cellulose family, which usually means soft hand, beautiful drape, and a more fluid feel.
When we put all three together, we have a midweight knit with moderate stretch and soft, liquid drape. That means it would be suitable for medium weight t-shirts, dresses, and cardigans. It would not be our first choice for activewear or swim, and it may not be the best option for a very lightweight tee where you want an airy, barely-there feel.
Every knit fabric is a combination of weight, stretch percentage, and fiber content. Looking at all three together will tell you far more than the fabric name alone.
Putting It All Together
You've learned how weight, stretch percentage, and fiber content each influence a knit fabric. Now let's put those concepts into practice.
The chart below is designed as a quick reference when you're planning a project. Start with what you want to sew, then narrow your options by weight and stretch before comparing fiber content to choose the feel, drape, and performance you're after.
When you're shopping online, don't rely on fabric name alone, be sure to read the online description carefully. At Surge, we include details like weight, stretch percentage, fiber content, opacity, drape, and suggested uses whenever possible to help guide sewists toward successful projects.
You do not have to understand every knit fabric term at once. Start with weight, stretch, and fiber content. Once those three pieces begin to click, choosing the right knit fabric becomes so much easier.
Save This Guide for Later
If you found this guide helpful, save the flow charts or bookmark this page so you can refer back to it the next time you're shopping for knit fabrics. We designed it to be a resource you'll come back to again and again.
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