When it comes to thread, size matters just as much as color or material. The size of the thread affects stitch strength, fabric compatibility and the finished project. But understanding sewing thread sizes isn’t always easy as there are multiple ways to measure it.

This will explain how thread size is measured, the different systems and help you get to grips with thread sizing terminology.

If you’ve ever wondered what thread weight, denier or Tex means this is for you.

Thread Weight and Thread Size

Thread weight and thread size are two related but different things. Thread weight is the length of thread that weighs 1 kilogram. Thread size is the thickness of the thread. A lower weight number means a heavier thread and a higher weight number means a lighter thread. Thread size is measured in units such as denier, tex or weight.

Why do I need to measure Thread Size?

Before we get into all the numbers and formulas you might be wondering why yarn count is so important. Here are just a few reasons why knowing the yarn count is crucial to fabric and garment production and sourcing.

Quality

Yarn count can tell you a lot about a yarn’s durability, strength and comfort. It will help you decide if a yarn and a fabric is right for what you want to do.

Price

Yarn count affects the price of the fabric. The finer the yarn the more expensive the product. Yarn count also affects the weight of the fabric which can again affect the price.

Purchasing

When you know yarn count you’ll find it easier to search for the fabric you want. You’ll be able to communicate better with a supplier and check the fabric you order is to the correct specification.

What is Sewing Thread Size?

Sewing thread size is a measurement of the thread’s thickness or fineness. This ensures you’re using the right thread for your application whether it’s stitching silk or reinforcing denim on your sewing machine.

The problem is there is no universal standard for thread sizing. Thread is measured using different systems each with its own method and notation. These fall into two categories:

1. Fixed Weight Systems – Based on the weight of a specific length of thread.

2. Fixed Length Systems – Based on the length of a specific weight of thread.

Each system gives you different information about the thread. By knowing these systems you’ll know what to look for when choosing thread for your projects.

Fixed Thread Weight Systems

Fixed weight systems measure the size of the thread by measuring how much a specific length of it weighs. These are the most common methods and include weight designations like Tex, Denier and Gunze Count. Here’s how they work:

Using a thread size chart is essential for understanding these fixed weight systems as it helps you choose the right thread size for your sewing projects.

Tex System

The Tex system is one of the most popular and widely used thread measurement system in the world. Tex measures the weight in grams of 1000 meters of thread.

• How it works: A thread labeled “Tex 30” weighs 30 grams per 1000 meters of thread.

• Quick conversion tip: The higher the Tex number the thicker and heavier the thread. For example Tex 60 is heavier than Tex 30.

Tex is preferred for its simplicity and consistency so it’s a good choice for industrial sewing where thread strength and performance needs to be defined.

Denier System

The denier system measures the weight in grams of 9000 meters of thread. This system is used in industries like textile manufacturing where thread and yarn is part of the process. Nylon thread measured in denier is a popular choice among sewists for its versatility with different fabrics especially when matching 100% cotton upholstery.

• How it works: A thread with a denier of 100 means 9000 meters of that thread weighs 100 grams.

• Understanding the thickness: Threads with higher denier values are thicker and heavier. For example a thread with a denier of 200 is thicker than one with a denier of 100.

Denier is used for materials like nylon, polyester and other synthetic fibers especially in apparel and upholstery applications.

Cotton Count (Ne or Gunze Count)

This system is used for cotton threads and measures thread size inversely. Unlike Tex and Denier a lower value in the Cotton Count system means a thicker thread.

• How it works: The Gunze Count is how many hanks (840 yards) of thread weigh one pound. For example a 40 Gunze thread means 40 hanks weigh one pound.

• Tip for interpretation: A Cotton Count of 20 is heavier and thicker than a Cotton Count of 50.

Cotton Count can be a bit confusing for beginners because of its reverse sizing but once you get used to it, it’s an accurate system to measure thread thickness.

Fixed Length Systems

Fixed length systems measure thread size based on how much thread length corresponds to a fixed weight. These include systems like Metric Count (Nm) and U.S. Thread Size. In these systems higher numbers mean thinner threads which is good for delicate fabrics to ensure strong and durable seams.

Metric Count (Nm)

Metric Count also known as Nm measures the length of thread in kilometers per one kilogram of weight. This system measures fineness by calculating thread length for constant weight and you need to consider different thread weights when adjusting machine tension for good stitch quality.

• How it works: A thread labeled “Nm 40” means 40 kilometers of that thread weighs one kilogram.

• Relation to thickness: Higher Metric Count means finer thread. For example Nm 60 is finer than Nm 30.

U.S. Thread Size

U.S. Thread Size used in North America is another length based system that serves similar purpose. However this system is less common in global standards and is mostly found in local sewing markets.

Fixed Length Systems are less intuitive for many users but are part of thread measurement standards especially in more specialized applications.

Yarn Count for Filament & Staple Yarn

How to check yarn count for filament yarn?

Yarn count of filament yarn is measured in denier (D). Denier can be calculated using a weight per unit length system where fabric weight is a constant. For example:

9000 meters of yarn = 1 gram = 1 denier

9000 meters of yarn = 100 grams = 100 denier

The bigger the denier number the heavier, thicker and cheaper the yarn will be. The smaller the denier number the lighter, thinner and more expensive the yarn will be.

You may see a yarn count that looks like this: 75D/72F. So what does this mean?

Filament yarn is made up of multiple filament fibers. The above figure means the yarn is 75 denier and 72 filament fiber strands.

If the filament number is greater than the denier – for example polyester 50D/72F – we call this yarn a microfiber.

Besides denier, there is another way to measure filament called Tex but it’s less common.

How to check yarn count for staple yarn

We can measure yarn count for staple yarn using a weight per unit length system.

The spinning industry likes to use a process based upon English Cotton Count. This yarn count is determined by the number of yarn hanks (each 840 yards long) that weigh one pound of yarn.

This method is measured in ne (not denier or tex) and is written as ‘s. For example “Cotton 20’s”.

840 yards = 1 lb = 1 ne or 1’s

840 yards x 2 = 1680 yards = 1 lb = 2 ne or 2’s

The bigger the number the finer the yarn and vice versa.

How to check yarn count for blended yarn?

We get yarns blended with two or more different materials for many reasons; to enhance a fabric’s properties, to reduce the cost and even to create different dyeing effects.

When it comes to measuring yarn count for blended yarn, it’s very simple. The measurement we use depends on the fiber form.

If the yarn is staple yarn we can use ne, ‘s or tex. If the yarn is filament yarn we use denier/filament.

Choosing the Right Thread for Your Project

Now that you know how thread size is measured you can choose the right thread for your stitching needs. When working with home sewing machines it’s very important to choose the right thread size for the fabric type for good sewing results. Here are some tips to help you:

1. For delicate projects: Use finer threads measured in higher Nm, Gunze Count or lower Tex and Denier.

2. For heavier materials: Use thicker threads like Tex 60 or higher, lower Gunze Count.

3. Always test first: Use sample stitching to see how the thread behaves with your chosen material.

Thread size is very important to the durability and looks of your stitches so it’s a key factor in any sewing project.