Cotton Lycra vs Rib vs French Terry: What’s the Difference?

Cotton Lycra vs Rib vs French Terry: What’s the Difference?

This blog is for you if you’ve ever browsed knit fabrics and wondered:

• “Do I have to use rib knit for cuffs?”

• “Can I use French terry for a t-shirt?”

• “Why are there different weights of Cotton Lycra?”

While all three are knit fabrics, and often have the same fibre content (95% cotton, 5% spandex) they behave very differently, and choosing the wrong one can completely change the fit and feel of your finished garment.

Today we’re breaking down the differences between cotton lycra, rib knit and French terry, plus sharing a free knit fabric comparison chart to make fabric decisions easier.

👉 Download the free knit comparison chart here. (or don't, because I haven't uploaded it yet!)

* A note on lycra - although lycra is commonly used in the names of fabrics across the industry, it’s technically a brand name, and the official name that is used in NZ to label to match labelling requirements is actually elastane. 

What Is Cotton Lycra?

Cotton Lycra (also known as CL, or called cotton spandex or cotton elastane) is a smooth knit fabric with fabulous stretch thanks to its lycra content. The name is often shortened to CL, with the weight in gsm listed after - e.g. we sell CL220 (220gsm) and CL270 (270gsm), and our solids are CL230. The main difference in these is the feeling in a garment, rather than necessarily a weight difference - CL220 is lighter, very stretchy and has great recovery. CL270 is slightly more compressive feeling, has slightly less stretch percentage, and would be ‘thicker’ feeling and tighter when worn if the same pattern was used. 

Key Features of 3am Threads Cotton Lycra:

• 4-way stretch (horizontal and vertical)

• Excellent recovery

• Smooth surface

• Medium weight (often 200–270gsm, we sell a 220gsm and 270gsm)

  
  

Best For:

• T-shirts

• Dresses

• Leggings

• Baby and kidswear

• Everyday basics

  
  

Cotton lycra is often the “default” knit fabric for garment sewing because it’s stable enough to sew easily, but stretchy enough to be comfortable. Please note if you have never used it that it is common for lighter weights of CL to roll at the edges once prewashed, or when cut - this can be flattened somewhat by ironing if really needed, weighted down, or pinned thoroughly, but doesn’t affect how the fabric sews together and eventually isn’t a problem once you’ve done it a few times!

*CL is often called Cotton Jersey in the UK and Europe. Cotton Jersey here generally refers to a fabric that is 100% cotton and has mechanical stretch horizontally only, so be sure to check your fibre content if you’re buying Cotton Jersey!

What Is Rib Knit?

Rib knit is designed with vertical ridges created by alternating knit and purl stitches. It contains stretch due to its structure, and then has added stretch that comes from the lycra content. Rib comes in either polyester or cotton blends - ours is 95% cotton 5% lycra. They come in various ‘rib’ widths, which refers to how many stitches create the ridge, and how many are in the dip. Our rib is 4x2, which we think looks lovely and is very soft against the skin. 

Key Features of 3am Threads Rib Knit:

• Extremely stretchy (especially horizontally)

• Strong recovery

• Textured, ribbed appearance

• Ribbed on the right side of the fabric only - the wrong side is mostly flat

  
  

Best For:

• Neckbands

• Cuffs

• Waistbands

• Fitted tops and dresses

• Matching sets

Rib behaves very differently from cotton lycra, even if the fibre content is similar. It stretches further and “snaps back” more firmly, which is why it’s often used for bands. If used to make the same pattern exactly as a cotton lycra, the rib version would have a firmer fit.

What Is French Terry?

French terry is a knit fabric that comes in two different types - looped or brushed. It has a slightly brushed surface on the front, but is generally smooth. Looped has small loops of fabric on the back, whereas brushed is ‘fuzzy’ feeling.

It’s thicker and more stable than cotton lycra or rib, but generally has less stretch and the recovery is often not as good. Often French Terry will have 2 way stretch only (horizontal) if the lycra content is low or the fabric has a very high gsm, so it’s always worth either checking the stretch percentage or getting a sample if you’re buying from elsewhere. Luckily, we’ve picked our favourite French Terry with all the features we like (including great stretch and decent recovery in both directions!) for you. 

Key Features of 3am Threads French Terry:

• 4 way stretch - horizontal and vertical (with bigger vertical stretch percentage, but don’t go cutting cross grain unless you really have to or your print might be sideways!)

• Lower stretch percentage than cotton lycra

• Soft looped back

• Heavier weight (280-300gsm depending on the batch)

  
  

Best For:

• Jumpers

• Light Trackpants

• Lightweight hoodies

• Relaxed-fit garments

French terry is ideal when you want structure and a little extra warmth without going full fleece.

Knit Fabric Comparison Chart: Cotton Lycra vs Rib vs French Terry

Here’s a simplified breakdown:

Feature	Cotton Lycra	Rib Knit	French Terry
Stretch Type	4-way	2-way or 4-way	Usually 2-way
Stretch Amount	Moderate–High	High–Very High	Low–Moderate
Recovery	Excellent	Excellent (with lycra)	Moderate
Weight	Medium	Light–Medium	Medium–Heavy
Texture	Smooth	Ribbed	Smooth front, looped back
Best For	Everyday garments	Bands + fitted pieces	Jumpers + loungewear

👉 Download the printable knit fabric comparison chart here.

When Can You Substitute One for Another?

This is our opinion, based on how we’ve used our fabrics. This isn’t to say it will always work, and it may take some trial and error, and it will also depend on how your pattern is drafted. 

Can you use rib instead of cotton lycra?

Sometimes, but expect:

• More cling

• More stretch

• A firmer fit due to the recovery

You may need to trim down cuffs or adjust neckbands to use rib if they’ve ben drafted to use cotton lycra. 

Can you use French terry instead of cotton lycra?

Usually, but only if:

• The pattern allows lower stretch

• The garment is relaxed fit

French terry won’t work well for fitted tees or leggings, but you could size up and have a baggier fitting tee that’s a little thicker than standard. For leggings or other bottoms, as long as you have a waistband that will hold them up (using something like elastic or CL) and they’re not too tight in the legs, you should be able to make it work if that’s all you have. 

Can you use cotton lycra instead of rib for cuffs?

Sometimes! Cotton lycra doesn’t have the same “snap back” structure rib does, so cuffs may stretch out over time, or feel tighter to get over the hands or feet. That said though, we use it often and find that if you cut them just a tiny smidge bigger than they 

Why Understanding Your Base Matters

Even when fibre content looks the same, structure changes everything.

Two fabrics can both say: 95% cotton / 5% lycra

But behave completely differently because one is rib and one is French Terry.

That’s why checking:

• Stretch percentage

• Recovery

• Weight

• Structure

are so important before cutting into your fabric.

If you’re unsure about stretch percentage, look out for our upcoming blog on how to calculate fabric stretch percentage here. 

Free Knit Fabric Comparison Chart

To make fabric choices easier, we’ve created a simple comparison chart that includes:

• Stretch type

• Typical stretch range

• Recovery notes

• Common uses

• Weight range

Print it out and keep it near your cutting table for quick reference when planning projects, or use it digitally, your choice!

👉 Download the knit fabric comparison chart here.

Sewing with 3am Threads Knits

If you’re browsing our preorder bases and unsure which one suits your pattern:

• Check the base info page for stretch percentage

• Use the knit fabric comparison guide

• Or, reach out through email or on our instagram page! We’re always happy to help.

Holly and Jen