A Quilter’s Guide to Thread Weight

There are two sewing aspects to quilting…piecing the top and the actual quilting of the quilt. You may want to use different thread weights (thicknesses) for each. As you head to the fabric store or quilt shop to buy your thread for quilting, you may be wondering what weight of thread to purchase.

In this blog, whether you use 100% cotton or polyester sewing machine thread, we’ll help you decipher what a thread weight means and which weight threads may be just right for your quilt projects. This way, you can make the best choices when you are looking for the perfect thread to make and finish your quilt.

Well, not really. Which means that one manufacturer’s/brand’s thread of a certain marked weight may not actually be the same “thread size or weight and therefore thickness” as another’s thread of a similarly marked weight. Why? It all depends on how that manufacturer measured the thread weight to begin with. Currently, there really isn’t a standard (or universal) global measurement that is used by all manufacturers. So, if you are comparing different brands of thread in a certain weight range then it is good to understand how thread weight is measured.

Most thread is made up of two or more plies (aka: strands or filaments).

So what does that look like? Two or more strands are twisted together to form the final thread. See the picture below for a good visual of what this means.

Simply put, thread weight measures the thickness of a thread. It does this by measuring how much (in length) of a certain thickness of thread is needed for a specific form of measurement. Are your eyes crossing yet? Mine are. But, stay with me here and read on for a bit more clarification.

There are several commonly used forms of thread measurement: Gunza Count, Number System, Weight, Tex, Denier and Cotton Count. We’ll go over how they get their numbers for each type of measurement. This way when you see…50/2, 50/3, #50 or No. 50, 50wt or 50-wt, 50NeC, 50s/3, etc. you’ll better understand what it all means. For this blog, I’ll mostly use the “50” weight example to keep things consistent throughout.

A measurement used for both cotton and polyester threads.This thread measurement originated in Japan and it measures both the thread size and the number of plies/strands or threads that are wrapped together to make the final thread. The most common representations of this thread measurement are: 50/2, or 50/3, etc. The first number here refers to the weight of the individual plies of thread before they are wrapped together. The higher the number the thinner the thread because it takes more thinner thread to equal the weight measurement used…though we don’t quite know the way it is truly measured. The second number indicates the number of strands that comprise the final thread.

So, 50/2 means there are two plies of size 50 weight thread twisted together. While 50/3 weight means there are three plies twisted together making this thread both thicker and stronger than the 50/2.

Another measurement used for both cotton and polyester threads. Sometimes you’ll see #50 or No.50…these also originated in Japan as part of the Gunza system but do not necessarily correlate to the actual thread weight because the numbers can be referring to 50wt (as explained below). Sometimes you get a “Composition number" that refers to weight and plies such as 50/2 or 50/3 thread (system used by some other countries). Which means they can all be different weight threads so you’ll need to rely on your eyes and fingers to gauge the thickness of the thread.

To make matters more confusing…thread importers in the United States often labeled #50, 50/2 or 50/3 all as 50wt. We can see from the explanation above that threads with these different numbers are not all the same thickness. Which means that not all 50wt threads are created equal as I alluded to in the beginning of this blog. This becomes important when comparing thread brands that have the same 50wt label. Again, you’ll need to use your eyes and fingers to determine the difference between the different brand’s 50wt threads.

This measurement is referenced as “wt” on a thread spool. It can be a representation of #50, 50/2, or 50/3, etc. as explained above.

-Or-

It can mean that 50 kilometers of that thread weighs one kilogram. As this one is measured by how many kilometers of thread weigh one kilogram this will mean that the higher the number, the thinner the thread. You’ll see weight shown on spools as 50-wt or 50wt

Having two different meanings to “weight” makes using the “wt” number on a spool not only a bit confusing when comparing threads from different brands but not necessarily accurate. So you’ll want to use your eyes and fingers to make the comparison more so than the numbers on the spool.

Regardless, this is the most commonly used label and measurement when discussing thread weight. Which is a problem since there is no set way that wt is actually used as it could be a result of the #50, 50/2, 50/3 or an actual measurement based on how many kilometers of thread weighs one kilogram.

This is a commonly used measurement for synthetic threads of which polyester is one. This measurement looks to see how much 1000 meters of thread weigh in grams. So, if 1000 meters of “Thread A” weighs 25 grams then it is 25 Tex or 25 T. If 1000 meters of “Thread B” weighs 70 grams then it is 70 Tex. A 25 Tex thread is thinner than a 70 Tex thread. So in this case, the lower the number the thinner the thread. This is good to know if you happen across a thread that is measured in Tex. You may also see a “wt.” measure on the thread spool.

This measurement is often used for synthetic threads, including polyester. Originally used to measure silk, Denier looks to see how much 9000 meters of thread weighs in grams. So if 9000 meters of “Thread A” weighs 150 grams then it is considered 150 Denier. Similar to Tex measurements, the lower the denier number, the thinner the thread. It is noted on thread spools as Den, Td or d so you may see Den 150, 150 Td or 150 d, for example.

This measurement as its name suggests is used for cotton thread. Cotton Count looks to see how many hanks of 840 yards each equal one pound. So if one pound of “Thread A” is 50, 840-yard hanks, then you have a 50 NeC (sometimes denoted as NeB or Ne) thread. The higher the NeC number, the thinner the thread. By the way, NeC stands for “Number English Cotton” just in case you wanted to know why this one wasn’t something like “CC” instead.

This is similar to the Cotton Count but is based on the metric system. In this method of measuring, you are looking to see how many 1000 meter hanks of thread weigh one kilogram. So if 50, 1000 meter hanks weigh one kilogram then you’ll see Nm 50 on the thread spool. In this measuring system, the higher the number the thinner the thread.

You may also see 50s/3 on a thread spool. This can mean a 50 weight thread made of three plies. Or it can mean the thread if made of three 50 weight plies of thread. Again, if you are comparing brands, you’ll need to use your eyes and fingers to judge between them.

There are many different ways that thread weight and therefore thickness is measured. And the labeling (some that doesn’t follow any of the measurement systems or lack of labeling in some cases) is only a guide to where a thread fits into a brand's threads. Again, we recommend you use your eyes and fingers to judge between different brands of the same “weight” to see which one you want for your project.

When you are piecing and when you are quilting you want to use different weight threads to achieve different results. Every thread weight has a use in quitting. Let’s take a look at how each one can help you in your quilting journey. As “wt” is the most commonly used way to talk about thread weight, we will do that here too.

NOTE

When matching the needle to the thread, you will be looking to make sure that the thread moves smoothly through the eye (hole) in the needle that you are using so that it doesn’t get stuck causing it to shred or break. This means that you might have to test one or two needle sizes with the thread you are using to make sure the needle works. When working with the thicker threads, you’ll want to keep the speed down on your machine. When testing, you’ll know you need a larger needle size if you are seeing skipped stitches or the thread is shredding at the needle.

Below, we’ll give some popular needle size/type recommendations for you to start with.

This is a heavier and thicker weight thread…some would even say it’s chunky. Use it to make big straight stitches that are thick and really stand out. This is not a thread weight to use if you want subtle! And, it’ll take some practice to make your stitches look smooth and even when using a sewing machine. You should definitely stitch slowly while using this thread.

NOTE

Most often, this weight thread is used for hand stitching as it is a little tough to use on a machine…though it can be done with some practice.

Use a 100/16 top stitch needle.

These thick threads are just a little heavier than the mid-weight threads and will give texture, definition and depth to your quilt. They won’t be as thick and heavy as the 12wt thread but they will boldly sit on your quilt and be noticed. If you want your stitches to pop, be visible and shine in the spotlight, these are the thread weights to consider for your quilting. Great for free-motion quilting things like feathers, etc.

You’ll want to practice when sewing with these as these threads are denser than the often used 40wt or 50wt threads. But, once you get the hang of sewing with these threads, you might find that they are just what your quilt design needed. And they will hold up well in well loved quilts.

Use a 90/14 (topstitch or embroidery) needle when using a 28wt thread. Use a 90/14 - 100/16 (universal) needle when using a 30wt thread.

This weight thread will make your quilting stand out without shouting out. It’s good for straight-line or free-motion quilting. It has more strength than a 50wt thread so it’s good for items that will get a bit more use or washing.

Use a 80/12 - 90/14 universal needle.

This weight thread is the most popular weight used for piecing quilt tops as it is thin enough to not add bulk to your seams and strong enough to hold them together. It is also used by many for all kinds of quilting including stitch-in-the ditch, straight-line and free motion. The quilting will be more subtle than it would with thicker threads but it won’t disappear either.

Use a 80/12 universal needle.

This weight thread will make your quilting melt into the background allowing the fabric to be more of the star. It’s also used when piecing small pieces together. If you have a lot of close quilting but don’t want your quilt to get too stiff consider using this weight thread. This thread is thinner and not as strong as 50wt so keep that in mind.

Use a 80/12 universal needle.

This weight isn’t an often used thread size for machine quilting. It will melt into the background even more than 60wt. It is more often used for piecing small pieces as it adds the least amount of bulk to a seam.

Use a 70/10 - 80/12 universal needle.

When you are shopping for thread, you can easily compare one weight to another in the same brand. If you are comparing the same weight thread across brands, your best indicator of thread size and weight will be your eyes and your fingers. Especially since some brands don’t even have weights on them to give you a ballpark idea of where they fit in the weight scheme of things.

When quilting, you may want to test a few different thread weights on “scrap quilt sandwiches” to see how those threads look when you straight-line or free-motion stitch. Different thread weights will give your different effects and looks.

You will also want to consider how often and how much wear and tear your finished quilt will get and then choose the threads that will hold up to it. And finally, you just might need one or another weight thread based on the size of the pieces you are piecing.

This blog is just meant to be a guide or starting point for you as you explore the fascinating world of quilting.

If you are looking to try out some different weight threads to test them out. Check out the blogs below for some inspiration:

• Free motion quilting takes some practice. Don’t be afraid to try it though. If you never have, this blog about how to free motion quilt for beginners is a nice introduction or refresher!

• Decorative stitches are fun to add to quilts and other projects. Find out how easy it is by reading our blog about thread sketching with your sewing machine.

• Want a quick and easy quilt project where you can make it fast? Our Quilted Hot Pads for Your Kitchen Blog is a perfect little project to try. And, it’s an easy one to test different weight threads with too!

• Bowl Cozies are a popular item found at craft fairs. If you want to learn to make your own or ones to sell then our blog about Sewing A Bowl Cozy is perfect for you. So get out your 100% Cotton thread and give this project a try.

Cathy Jaynes
Product Developer and Quilter