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How To Tell If Fabric Is 100 Cotton?

Knowing if your fabric is 100% cotton is a key factor in making sure you can care for it the right way. Cotton and cotton blend fabrics may look similar. But, they don’t have the same properties. So how do you tell if your fabric is 100% cotton?

You can test fabric for 100% cotton using the burn test. Take a few fibers and hold them against a flame. 100% cotton will not curl from the heat. It smells like burning paper and leaves grayish ash without signs of melting. 100% cotton is easy to tear and is super soft when held against your cheek.

Identifying 100% cotton is not as hard as you think. Read on to find out what you need to look for to tell if the fabric is 100% cotton.

How To Tell If Fabric Is 100 Cotton

What Is 100% Cotton?

Cotton is a natural fiber made from the protective outer coating of the seeds from a cotton plant. When made into a fabric, it’s soft, breathable, and hypo-allergenic. Because of its natural properties, it’s also biodegradable.

When joined together, the cotton fibers made into thread for sewing or fabric. Cotton fabric is woven and can be purchased in different weights. There are three different weights of cotton. Lightweight cotton is suitable for summer like voile, lawn, and gingham. Then there is the medium-weight utility cotton-like quilting cotton. Finally, there is the heavyweight workhorse cotton, like denim, flannel, and canvas.

Most cotton fabric can be blended with something else. Sometimes Lycra is added to give the fabric some stretch. The addition of polyester can stop your cotton shirt from shrinking.

If the label on your garment says 100% cotton, it means there are no other fabric fibers present. Your tee-shirt or summer top is made from cotton fibers and nothing else.

Is 100% Cotton the Same as Pure Cotton?

The term pure cotton is slightly different from 100% cotton. Whereas 100% cotton is a fabric or garment made from nothing but cotton, the same is not necessarily true of pure cotton.

The term pure cotton refers to the cotton content within a fabric. It confirms the cotton used is pure. However, the term does not indicate that the fabric or garment is only made from cotton. A garment containing pure cotton can be a blend. There is a possibility that it could be a polycotton.

Only garments and fabric listed as 100% cotton are guaranteed to be made of cotton and nothing else. If you want to make sure you are getting cotton, look for tags that stipulate 100% cotton.

Why Test if Fabric Is 100% Cotton?

There are several reasons why it’s important to know if your fabric is 100% cotton. The first reason is wearability. As it’s a natural fiber, cotton is less likely to irritate delicate skin, making it ideal for babies and those suffering from skin allergies. Its natural cooling properties and moisture-wicking abilities keep you dry, cool, and comfortable.

A second reason to test for cotton content is the use you have in mind for the fabric. 100% cotton is great for apparel and home décor. You can use it for anything that doesn’t require stretching. If you need fabric for something like activewear, or swimwear, you need to make sure it isn’t 100% cotton because it will be unsuitable for that use.

Knowing how to care for the fabric is another reason to test for cotton content. Most fabrics have different care instructions. 100% cotton can withstand a certain amount of heat. Polycotton can’t. Before you start ironing your cotton shirt on the highest setting, you need to make sure it’s cotton and not a synthetic blend.

If sustainability and being environmentally friendly are important to you, using 100% cotton can help ensure you reduce your carbon footprint. Synthetic fibers are made from petroleum by-products, a bit like plastics. Unlike cotton, they are not biodegradable and can be difficult to dispose of.

How to Tell if Fabric Is 100% Cotton With the Burn Test

How to tell if fabric is cotton

One of the easiest ways to test for 100% cotton is with the burn test. It sounds a little drastic but is quite effective in helping to identify natural fiber content. If the garment has a tag, check to see if it lists the fiber content before resorting to snipping bits out of your clothing.

Step 1: Cut a small piece of the fabric from an unnoticeable area.

Step 2: Set fire to it.

Step 3: Pay attention to the color of the smoke and how the fabric burns.

Step 4: Check the color of the ashes left behind.

100% cotton will burn without shrinking away from the flame. It will emit a similar smell to paper or wood burning and leave grayish ash behind.

Polyester blends will show signs of melting as the synthetic content reacts to the heat. Wool and silk will both shrink away from the flame. Wool gives off a strong smell of burning hair, while silk can smell like burning meat.

The one main drawback with the burn test is most natural, plant-based fibers behave the same way as cotton. Flax, jute, and hemp all have similar characteristics and will give the same results.

It may be necessary to use the burn test in conjunction with other methods to identify cotton content. This includes using sight and touch.


How to Tell if Fabric Is Cotton Without Burning [by Touching]

How do you know if fabric is 100 cotton

Cotton, especially 100% cotton, can be quite stiff. This is particularly true when it comes to quilting cotton, medium-weight cotton known for its firmness. The stiffness makes it easy to crease and hold a fold line.

Even if you press with your fingers, it’s enough to mark the fabric. Although the fabric usually softens after washing, it will still be easily creased. This is true for all kinds of cotton, from summer weights through to the heavy winter weights.

100% cotton will feel cooling, have a slight texture and be soft against your skin. One of the best places to test this, close your eyes and feel the fabric with your face, preferably the cheek. Doing the same test with a different fabric, silk, for instance, will give different results. Silk will feel smooth but slippery and cold.

Polyester and polycotton blends will feel smoother than 100% cotton and will slide across the face easier. Wool will be scratchy and coarse.

Fabrics made from 100% content don’t stretch. They do have a little bit of giving, but on the whole, they are rigid materials giving structure to a garment’s shape.

If your fabric or garment feels cool and soft against your skin, has a firm, structured shape, and creases easily, then chances are it’s 100% cotton.

How to Tell if Socks Are 100% Cotton

Socks made from 100% cotton will feel soft and cozy on your feet. As cotton is a breathable fabric, your feet will also stay cooler for longer. If there is any polyester content in your socks, they will feel clammy against your skin.

Polyester doesn’t absorb water as it’s naturally water-resistant. When blended with cotton, it reduces the fabric’s ability to allow moisture to evaporate. Leaving your feet feeling hot and sweaty.

The price of your pair of socks is also a good way of telling if they are 100% cotton or not. Cotton can be expensive. If your socks were a bargain, they could be a cotton blend.

How to Tell if Shirts Are 100% Cotton

100% cotton shirts are comfortable and cool, especially in warm weather. Cotton is well known as the ideal fabric for hotter climates because it allows moisture to evaporate. A shirt made from a cotton blend is more likely to retain moisture making you hot and sweaty.

One of the drawbacks of cotton is it’s a slow-drying fabric. When it comes to identifying the fabric, this can be an advantage. If you wet the shirt, time how long it takes to dry. A long time will indicate the likelihood of 100% cotton content. Fast-drying could mean it’s a polycotton.

A polycotton shirt feels smoother and more silk-like than 100% cotton. It’s also less prone to wrinkles meaning your shirt doesn’t need ironing so much.

The best way to make sure you are getting a 100% cotton shirt is to make sure it says so on the label. If that isn’t possible, check how quickly it dries and how it makes you feel when you wear it. Try it on in the store before you buy so you can see if it’s soft and textured like cotton. If it’s smooth like silk, it’s probably a blend.

Which Is Better 100% Cotton or a Polyester Blend?

Whether you go for a polyester blend or 100% cotton depends on what the garment is and your individual preference. As cotton is a natural fiber, it has a few advantages over its synthetic friend.

Cotton is comfortable and unlikely to irritate skin disorders. It’s an ideal fabric for garments worn next to the skin for this reason. As it allows moisture to evaporate, there’s no build-up of sweat on things like bedding or undergarments. Cotton can be expensive, though. This is why it’s cheaper to buy a cotton blend.

Manmade fibers like Polyester don’t breathe. This can make garments made from synthetics too hot and sticky for warm or humid climates. Trapping heat and sweat close to you instead of allowing moisture to evaporate.

In cooler regions, cotton can help keep warmth in as the fabric is heavier than ones containing synthetic fibers. Polyester, on the other hand, can be a bit chilly due to its light, airy properties.

Cotton tends to shrink, though. Regular washing can cause it to deteriorate faster, meaning 100% cotton garments may not last as long as one with manmade fiber content.

Mixing the two gives you polycotton and, to a certain extent, the best of both worlds. You get some of the breathable qualities of 100% cotton combined with the longevity of the polyester fibers. Coupled with an overall feeling of lightness, a cotton-polyester blend will be less likely to wrinkle.

Polycotton blends are known to be hot and clammy in warmer climates, though. The final choice between the two is down to where you live and what you need a garment to do. If you need a garment to withstand regular washing, go for polycotton. For comfort and coolness in a hot climate, 100% cotton is best.

How to Tell if Thread Is Cotton or Polyester

When you buy thread, the label will say if it’s 100% cotton or 100% polyester, or even a blend. If it’s a thread you’ve had for a while, you may have lost the sticky label from the spool. In that case, you’ll need to test the thread.

Testing sewing thread for fiber content is the same as for cotton fabric. You need to carry out a burn test.

Step 1: Cut a small piece of thread measuring about 6 inches.

Step 2: Set fire to it and watch for the color of the smoke.

Step 3: Pay attention to the smell and how the thread reacts to the heat.

Step 4: Look at the color of the ash.

Thread with a polyester content will melt. A silk thread will curl or shrink away from the flame.

A 100% cotton thread will not curl away from the heat. It will smell like burning paper or wood and leave

grayish ash behind.

Unfortunately, as with the burn test on fabrics, it will be difficult to tell cotton from other plant-based threads as they will all act the same. Cotton and polyester, or a mixture of the two, are the more popular threads for sewing, so there’s a good probability your thread will be one or the other.


The best way of telling if you have 100% cotton fabric is by checking the label. If that isn’t possible, pay attention to the look and feel of the fabric. Try getting it wet and see how fast it dries. If it’s a fabric you already own, and as a last resort, try the burn test.

Let me know in the comments if you liked the article. Has it helped you identify 100% cotton?