Guide to All Things Thread

Let’s talk thread. When I first started quilting, I just grabbed whatever was labeled ‘quilting thread’ off the shelf at my local JoAnn’s and went with it. I didn’t find out until later on that there was a whole host of thread varieties available and then it became very overwhelming. While I am a firm believer that the best way to find your favorite threads is just to experiment, that can be an intimidating and expensive prospect. So, to get you started, I thought I’d share my favorite threads


  1. Thread Basics

  2. Fiber Type

  3. Thread Thickness

  4. Ply

  5. Threads for every purpose

  6. Piecing

  7. Foundation Paper Piecing

  8. Quilting

  9. Garments and bags

  10. Decorative thread

Thread basics

First things first, let’s get a few terms straight. Don’t let this overwhelm you. It gets a bit into the weeds, but it’s there for completeness; skip this section if it’s boring or overwhelming. Threads can differ in 3 main ways: (1) fiber type, (2) thread thickness, and (3) the number of plys.

Fiber type

Sewing threads come in a number of different fiber types (wool, silk, nylon, cotton, and polyester, to name a few). These fiber types can be roughly grouped into two different categories: (1) natural and (2) synthetic. Natural fibers will burn (rather than melt) and are generally weaker, but less stretchy than synthetic fibers which are exceptionally strong but will melt when exposed to high heat and tend to stretch slightly. Of the fiber types available, cotton and polyester are by far the most common so I will confine the rest of this discussion to primarily those two fiber types.

Thread Thickness

Thread thickness primarily refers to the diameter of the thread. The measure of thread thickness in the US is primarily weight (Abbreviated: wt on most labels although occasionally you will see it abbreviated as # as well, i.e. #40 thread. These are essentially the same unit.) However, this unit is a little misleading since it doesn’t take into account ply. More on that later.

In the rest of the world, a number of other units describing the thread thickness are used. Tex is the most universal (although Denier and Ticket Number are also used). Tex is simply the number of grams that 1000 meters of thread weighs. So, if the same length of thread (1000 meters) weighs more than that of another thread, it would have a higher Tex number. Bigger number = thicker thread. The wt unit is annoyingly exactly the reverse: higher numbers = thinner threads.

One more thing to note: since polyester threads and cotton threads have slightly different densities, threads with the same diameter will have a slightly different Tex number. This is not the case with wt. A 3 ply 40 wt cotton thread should be approximately the same diameter as a 3-ply 40 wt polyester thread. For reference, a standard 50 wt cotton thread is around Tex 35.


Ply refers to how many individual strands are twisted together to make the final thread. Almost all threads (except for monofilament) are not a singer fiber strand but rather a twist of several sub-strands.

If a thread is composed of two sub-strands, it’s said to be 2-ply. If three strands, 3-ply. Here’s where the wt unit gets a little confusing. While the sub-strand thickness is the same, a 2-ply thread will obviously be thinner than a 3-ply thread with the same diameter sub-strands. However, they will both be labeled as the same wt, 40 wt for instance, despite the 3 ply being roughly 50% thicker than the 2 ply. Often threads will be labeled as 2 ply or 3 ply. My rule of thumb is that if they’re not, and that information isn’t available on the manufacturer’s website, it’s probably not a high-quality thread and I shouldn’t be buying it anyways. Neither 2- or 3-ply is necessarily better than the other, just realize that there will be a thickness difference.

Threads for Every Purpose

Phew, now that that is out of the way. Onwards to my favorite threads for each purpose.


First up, piecing. For piecing, cotton thread is a requirement. This is because cotton thread stretches less than other fibers and we don't want our piecing seams stretching and causing inaccuracy. It's also readily available and comparatively cheap. I like a thin thread; as thin as I can reasonably get. For me, this means 50 wt. 2 ply or 3 ply is fine (although 2 ply will be thinner). My favorites are Wonderfil Konfetti Cotton 50 wt (not an affiliate link) or Aurifil 2 ply 50 wt Cotton (not an affiliate link). You can see a head-to-head comparison of these threads here, although any high-quality cotton thread will work. My only requirement for piecing is that it be cotton and that it be fine, i.e. 50 wt or higher. This makes my seams crisp and flat which makes it easier to achieve precise point matching.

Foundation Paper-piecing

Up next is a very specific kind of piecing: foundation paper piecing (FPP). If you haven’t given it a try yet, it’s lots of fun and allows you to make highly intricate and realistic pieces without having to resort to applique. In FPP, seams are stabilized by paper and several seams can stack up on top of each other leading to super bulky seams. For this reason, I like to use an extra-fine thread. Because the seam is stabilized by paper, I can break my traditional piecing ruler and be OK with the stretching introduced by using a poly thread. Poly threads are routinely made thinner and strong than cotton threads so it’s easier to find very fine poly threads. My go-to for FPP is Decobob by Wonderfil (not an affiliate link). Decobob. It's an 80 wt polyester thread and produces beautifully flat FPP seams even when you get a lot of buildup. I never FPP without it.

Of worth noting is that Wonderfil also makes a 100 wt poly thread, Invisifil. I shy away from using it for FPP simply because I’m a little wary of the strength being able to stand up to the tugging and man-handling that goes on when removing papers from FPP. 80 wt gives me the right combination of thinness and strength.


When it comes to quilting my sandwiched quilt tops, I tend to use a lot of different threads. However, if the thread is going to be structural, i.e. it’s going to be the thing holder the quilt together, my unbreakable rule is that it must be a polyester thread. My quilts, which get used and washed to death, undergo a lot of tugging and pulling in their lifetime and that can pop stitches if those stitches were made of cotton thread. Because polyester thread stretches slightly, those stitches will hold up much better over time than a cotton thread of equal thickness. Don’t believe me? You can see a really good visual of this below. Poly is the only way to go for structural quilting stitches.

My go-to polyester quilting threads are Fil-Tek Glide, (not an affiliate link) a 40 wt (Tex 27) polyester thread, and So fine! (not an affiliate link) a 50 wt 3-ply polyester (Tex 25) thread from Superior Threads. I use Glide when I want a thread with a sheen to make the quilting a little easier to see and So Fine! when I want the quilting stitches to be a little less obvious since it has a matt finish.

Occasionally, I will also reach for Invisifil 100 wt 2-ply poly thread (not an affiliate link) from Wonderfil. This is what I use instead of monofilament because it’s easier to get in large quantities. The thread is so fine, that I can put white thread even on dark fabric and the quilting still blends in nicely. You can definitely still see it, but it isn't glaring like a thicker white thread would be and, after all, you'd still be able to see the light-colored mono-poly threads on dark fabric as well (nothing is ever completely invisible).

100 wt is perfect for quilts with lots of contrasting colors for which it would be impossible to find just a few thread colors that would blend on all the fabrics. It’s also extremely forgiving of free motion quilting mistakes so if you’re not entirely confident in your skills yet, try a super fine thread (80 wt or 100 wt). It’s like magic! The mistakes are still there, but they don't draw the eye like they do with a thicker thread.

Garment and Bag Sewing

I don’t sew garments often, but on the occasion that I do (without a serger), I always reach for a polyester thread. The same with bags (which I make frequently to stock my Etsy shop). Glide is my go-to for both because the polyester stretches slightly and is very strong. This yields a very durable final product that is going to experience A LOT of wear. I like the 40 wt thickness because my stitches show more on the decorative topstitching which I really like.

Occasionally, I'll even reach for a thicker, bonded polyester thread (bonded = coated for high-speed, industrial machines. Many machine quilting threads are bonded threads) to make them show more. The key here is polyester; I never use cotton for anything that is going to be tugged and stretched a lot.

Decorative Threads

My favorite decorative thread is metallic thread There's just something so extra about adding a little gold or silver to a project. I use them strictly as a decorative accent; no structural stitches. They can be a bit of a bear to work with, but a few easy changes can make it much more manageable and they're too much fun to just avoid.

Metallic threads' finicky-ness is largely due to their 'memory,' which basically means that when you unravel them off the spool, they act like springs rather than floppy string. This makes them VERY difficult to weave through your thread guides smoothly because that spring-like nature makes them want to twist and tangle like crazy. They truly have a mind of their own! Frequent thread breakage and jamming aren't uncommon.

To avoid this, a little investment in a notion makes all the difference. I use the thread dispenser (not an affiliate link) by Wonderfil. which corrals the thread as it comes off the spool not letting it twist and also preventing too much from unraveling at once. It works by making the spool rotate to unravel, rather than remaining stationary. That little change basically eliminates all the issues. I use it on my longarm too. If you don't want to invest in a thread dispenser, using an external thread stand to give yourself more room and using a thread net can also help.

Currently. my favorite metallic thread is Spotlite (not an affiliate link) by Wonderfil which is a rayon core with metallic foil wrap 40 wt thread. It literally looks like you're sewing with gold (pictures do not do it justice!) and it's perfect for those Christmas projects. Since metallic threads are also more delicate and prone to breakage than other threads, make sure you have your tension as low as possible while still maintaining correct tension balance and use a large eye topstitch needle. Using a thinner thread (such as 80 wt) in your bobbin can also help.

Other decorative threads I like to use include variegated and heavyweight threads (30 wt and thicker). Pretty much anything goes, just remember to always use a large topstitch needle (100/16 or even larger) and the thicker the top thread, the thinner the bobbin thread. I frequently use Decobob 80 wt in my bobbin whenever I'm using something thicker than my go-to 40 wt Glide on top. This allows the thick top thread to not bend so much to form the stitch and is easier on your machine.

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