When I was learning, I really had a fondness for sewing the same garment with different-sized threads. I realized it actually meant something in sewing, apart from fun. And that was ‘the thread thickness’.

Lightweight fabrics need thin threads for stitches. And, thick fabrics need thick threads to hold stitches.  

For beginners, this article on ‘sewing thread sizes’ will help you choose the right-sized thread for a particular fabric. I have also shared a glimpse of sewing threads’ type (sizewise), such as: Tex, Weight, Denier, and Cotton / Metric Count (Ne / Nm)!

So, let us move ahead and learn more about them below:

4 Types Of Sewing Thread Sizes:

In old times, people tried to weigh these threads in different metrics. Later on, the ISO- International Organization for Standardization formalized these systems.

Let us see some of the most commonly used types of thread thickness:

1. Tex: 

Tex stands for textile. It is considered an International Standard (ISO) for sewing machine threads. It is a direct method of measuring thread size. I find it really easy for beginners to understand. 

In this system, the weight in grams of 1,000 meters of that thread determines the ‘tex’. 

For example, 1,000 meters of Tex 40 thread weighs 40 grams.

Or, 1000 meters of Tex 50 weighs 50 grams.

Tex Sizes Are Generally Categorized As:

The math is simple here. The higher the Tex number, the thicker the thread. 

2. Denier (D):

I grew up measuring thread sizes either by tex or weight. After coming to the USA, I wanted a bulk quantity of thread for my shop.

I observed that many shops were offering thread in Denier sizes. TBH- I was really confused at first. But it is much simpler than it seems. 

In easy terms, I convert Danier like this:

Denier’s Formula:

Denier=9×Tex

A denier is the total weight in grams of 9000 meters of yarn or thread.

It Also Means:

A thin thread is considered low-denier.

And, a thick or heavy-duty thread is considered a high-denier.  

Denier Weights Are Categorized As:

Whenever I want to measure synthetic fibres such as polyester, rayon, nylon, satin, etc., I use this system. I prefer it, because it’s easy to understand for such threads and very reliable. 

3. Weight- WT:

This system is more common than Tex and Denier.

The weight (WT) is the number of kilometers of thread it takes to weigh 1 kilogram.

 For e.g. 30 WT thread size means 30 kilometers of that thread weighs 1 kilogram.

More thread length is needed to match the same weight. So, the thread is much thinner. 

It also means that the higher the weight, the thinner the thread.

Weight Size Of Sewing Threads Is Categorised:

4. Cotton / Metric Count (Ne / Nm):

4.1. Nm:

The term ‘Nm’ stands for Numéro Métrique (Metric Number).

Nm In Sewing Thread Is Measured As: 

Nm = Length (meters)/ Weight (grams)

I can explain to you this formula in easy words:

The Cotton Nm (Number Metric) shows the actual number of meters of thread that weighs exactly 1 gram.

For e.g. an Nm 40 thread means 40 meters of that thread weighs 1 gram.

The higher the Ne/Nm number, the thinner the thread.  And the lower the Ne/Nm number, the thicker the thread. 

If you visit a thread shop, you must have seen threads with size Nm 40/1, Nm 50/1, etc.

The ‘/1’ means the ‘Ply’- the number of threads twisted together.  In this case, it is 1. 

For e.g. 

A Nm 40/1 thread means 1 strand of thread where 40 meters weighs 1 gram.

Nm 40/2 contains two Nm 40 threads twisted together. So, each thread has a count of 40 meters per gram.

4.2. Ne:

The term Ne means the ‘Number English or English Cotton Count.’

It may sound confusing for beginners. So, I am explaining it in easy words:

The Ne shows how many hanks of 840 yards weigh 1 pound.

Ne Is Measured As:

Ne=Weight (pounds)/ Length (hanks of 840 yards)

For example, Ne 50 means 50 hanks of 840 yards weigh 1 pound.

Mathematically, Nm is 1.693 times Ne

Nm= 1.693×Ne

Here is a simple table to understand the relationship between these two metrics:

We can say that:

The higher Ne or Nm, the finer the thread. And, the lower Ne or Nm, the thicker the thread.

How to Match Thread to Fabric?

I always match the thread fibre to the fabric in terms of its size and texture. We need to understand that the thread should withstand the fabric’s thickness and tension.

• Lightweight fabrics: I use fine-sized polyester or silk thread for sewing delicate silk or chiffon fabric. It normally has a size of 60- 80 WT.

• Medium fabrics: I use standard all-purpose thread for sewing cotton, linen, polyester, etc. It has a weight of 40-50 WT.

• Heavy-duty fabrics: For sewing denim, canvas, cargo, or upholstery, I use heavy-duty polyester or upholstery thread. It has a size of 50-90 WT or more, depending on the fabric thickness.

Do you know? : The sewing thread must take 40% of the needle eye’s area. It reduces fraying or snapping when you sew at high speed.

Key Takeaways: 

Using the wrong size can lead to weak stitching. Tex, Weight, and Denier are the most common sizing systems used in domestic sewing. 

Out of these, tex and denier are direct systems. For Weight (WT), always remember- the higher the WT, the thinner the fabric! Ne/ Nm are a little tough to understand at first. But with the right practice, you will get used to it. 

FAQs:

1. Which Thread Is Thicker, 40 wt or 60 wt?

A 40 wt thread is thicker than a 60 wt thread. Because the higher the number, the finer the thread.

2. What Thread Size Is Used For General Sewing Projects?

Thread sizes of 50 wt, 30 tex, 40 Ne, or 68 Nm are commonly used for general sewing projects. They are easily compatible with sewing needles of size 80/12 or 70/10.