What is Thread Weight?

Threads and fabrics are the two most common and important elements in all types of sewing. In fabricating soft furnishings for the home, it is necessary for a good finished product to use elements that are suited for the application.

Let’s talk about thread. Using the correct thread can be the difference between success and failure. We wouldn’t use upholstery thread for sheers or a fine hand sewing thread for slipcovers. Therefore, it is important to know the correct size or weight of thread to use for each item to be sewn.What is thread weight? We all see those numbers next to the thread name. Did you ever wonder what those numbers mean? Thread is weighed or measured in 5 different ways: Weight (WT), Denier (Td or d), Tex (T), Number, and Composition.Weight is a length measurement and is determined by measuring the length of one gram of thread. If one gram of thread is 30 meters long then it is 30 weight thread. The higher the number the finer the thread.

Denier is also a thread length measurement and is the weight of 9000 meters of thread. The larger the denier number, the heavier the thread.

Tex is the most consistent of the thread measurement systems. It measures 1000 meters of thread in grams. One thousand meters of thread that weighs one gram is 1Tex. The higher the Tex number the thicker the thread.

The NumberSystem was developed in Japan and is called the Gunze Count system. It is used on finer thread and should not be confused with a weight measurement. It is designated as No. 50 or #50 for example. The smaller the number the heavier the thread is.

The Composition Standard was developed for cotton thread but has also been used for polyester. This can be confusing because a cotton thread and a polyester thread with the similar numbers aren’t always exactly the same. Compare cotton to cotton and polyester to polyester. Let’s look at a 30/3 thread. The first number is the same as the Number System explained above. The second number is the number of plies of thread twisted together. For our example, a 30/3 thread is a No. 30 thread with 3 plies twisted together.

So now that we know what those numbers mean, selecting the correct thread for the job is based on more than just guess work. With this knowledge we can also compare different threads for the qualities we need knowing that the job will go easier with the correct thread. Knowledge saves us time and money.Happy sewing!