Home Product Reviews The Ultimate Guide to Understanding Sewing Thread

The Ultimate Guide to Understanding Sewing Thread

by Sarah

Choosing the correct thread for your project starts with knowing the basic properties of thread and the options available. It can be overwhelming when you realize how many different types of thread are out there. The trick to thread selection is to choose the correct weight/thickness, fiber, and finish for your project. Generally speaking, All-Purpose Polyester thread works well for most general sewing projects. However, there are times when you may need to or may want to experiment with different types of thread.

We know it’s confusing, which is why we’ve created The Ultimate Thread Reference Guide. It’s the last thread reference you’ll ever need. We hope this helps and that you can continue to use this article as a reference throughout your sewing journey.

Let’s get started.

Thread is either animal-based, plant-based, synthetic, or a combination of those. In its simplest form, thread consists of two or more plies of “yarn” twisted together. It can either remain “soft” (untreated) or be treated with a special finish to increase its performance and appearance. A thread can be monofilament (basically, one long ply) or composed of multiple filaments (2 or more plies). Once it’s spun, it’s finished to accentuate project-specific features. It can be wax coated for shoemaking or silky smooth for low-lint quilting. It can even be finished with a vibrant, color-reflecting sheen, like quality embroidery thread.

Here are some of the terms you may come across:

Cord: When multiple “threads” are twisted together, they create a “corded thread”. These are commonly described as 4-, 6-, and 9-ply thread. As you can imagine, a corded thread will be stronger and thicker. You commonly see this used in leatherwork, shoe-making, etc.

Corespun Thread: This type of thread is composed of a “core” of continuous filament polyester that is wrapped with either cotton or polyester yarn, like a cocoon. These combined threads provide qualities from both fibers, with the outer fiber providing the finished “look”. For instance, a polyester core with wrapped cotton has the strength of polyester, but the finished look of soft cotton. This creates a stronger, more durable thread.  You commonly see this type of thread used in the construction of Jeans.

Ply: This is basically a strand of yarn. You’ll often see threads described as 2-, 3-, and 4-ply. The above image depicts a 3-ply thread.

Twist Direction: The direction the thread is spun defines its twist. It can either be twisted in a ‘Z’ direction (left twist) or a ‘S’ direction (right twist). A ‘Z’ twist is suitable for single needle sewing machines. An  ‘S’ twist thread isn’t commonly used in home sewing machines.

Thread Types

All-Purpose Thread: Your go-to, does-it-all thread. You’ll use this thread about 95% of the time. It’s acceptable for both hand and machine sewing. It’s compatible with nearly all fabric (lightweight to heavyweight). This thread is usually made of polyester or cotton. It’s not as heavy/thick as “heavy-duty thread”, nor as thin/light as embroidery thread. It’s perfect for constructing seams, edge stitching, quilting…it does it all. You wouldn’t want to use this thread with very fine, sheer fabric or very heavy denim or canvas.  It’s not suitable for projects that will withstand constant, direct sunlight or very high heat.

Clear Thread: Also called Monofilament and Continuous filament thread, this type of thread resembles a very fine fishing line and is useful when you want your stitches to be invisible. Depending on the weight, you’ll see monofilament thread everywhere from quilting to upholstery. Its nylon base makes it strong and able to withstand tension. Use clear on light fabric and the “smokey” tinted monofilament thread on very dark fabric.  We recommend using a thread net and a metallic needle when machine sewing with clear thread.

Embroidery Thread: This term includes machine embroidery and hand embroidery thread/floss. Embroidery thread is made from a variety of fibers, rayon being the most popular due to its high sheen and affordability. Though rayon is very popular, polyester embroidery thread has made large strides and is now stronger and more “colorfast” than rayon. You can also find embroidery thread made of cotton and silk. Rayon and silk embroidery thread works well for lightweight and medium-weight fabric, but a heavier fabric should be embroidered with polyester embroidery thread.

Embroidery Floss: Popular for hand embroidery and needlepoint, embroidery floss is either spun by hand or by machine into 6 strands.  It’s then divided to achieve the desired thickness (when the user is ready to embroider). Colors, numbering, and weights vary depending on the manufacturer. Pay close attention to the thread fiber make-up to determine how it will perform on your fabric. If you’re unsure, go by the feel of the thread and trust your judgment.

Elastic Thread: This type of thread is great for gathering and shirring fabric due to its high stretch and rebound. The trick to creating the most stretch is to hover your steam iron over the sewn elastic thread. Doing this will dramatically shrink the thread. By shrinking the thread, you create more gathers while still maintaining elasticity. After this, you can wash and dry normally without continued shrinkage.

Heavy Duty Thread: This thread is engineered to withstand high stress and tension. It comes in a variety of weights and finishes depending on what it’s meant to sew. For example, a heavy-duty outdoor thread will be thick and resistant to UV rays and may contain water-resistant properties (depending on the manufacturer). Consider heavy-duty thread when sewing heavyweight fabric (like canvas or duck cloth) that will encounter a lot of wear and tear. Camping gear, luggage, and sports equipment are examples of projects that benefit from a heavy-duty thread.

Industrial Thread: Industrial machines are built to sew daily at faster speeds and for long hours. They can handle everything from chiffon to stacks of leather. “Industrial thread” is really a 2-part term; it can either describe the spool size (like a 5 lbs spool) or convey strength not found in the home-sewing realm (like Kevlar Thread).

The industrial thread market is also where you can find the strongest, most durable, and most long-lasting thread. So, the term “industrial thread” can also mean “industrial strength”, like the strength needed to sew firefighter’s jackets, rock-climbing gear, and parachutes.

Jean Thread: This thread is designed specifically for sewing denim and is a little bit thicker than All-Purpose thread. Many manufacturers use corespun thread comprised of a polyester core wrapped in cotton. We recommend using a Jean Needle and choosing classic gold or blue-grey hues. You’ll also find denim thread that is slightly variegated to blend in nicely with denim fabric when darning.

Metallic Thread: Metallic thread is used to embroider and sew decorative topstitching. It isn’t very strong and breaks easily, which is why it needs the “white glove” treatment. It’s usually made with a polyester core and wrapped with slivers of metal foil/tinsel. Do not use with high heat or steam, as it will weaken and destroy the stitches. When used properly, metallic thread is beautiful and is always worth the extra effort. Before you sew metallic thread, read our tips and tricks for sewing metallic thread.

Quilting Thread: Generally, quilting thread is either cotton, polyester, or a blend of both. Quilting thread is mercerized for increased strength and color longevity. It’s gassed to reduce lint and designed to smoothly pass through the fabric without damaging it. Generally, you can use machine quilting thread for hand quilting as well. Popular quilting thread brands are Aurifil and King Tut.

Serger Thread: Overlock machines use 2 or more spools of thread to both construct a seam and/or finish the raw edge. To prevent bulk, serger threads are generally a bit finer than traditional sewing machine threads. Even though the thread may be finer, the end seam is still strong, durable, and flexible because it’s composed of multiple threads (usually 3 or 4). Because so much thread is used, serger thread is wound on large cones with about 2,000 to 3,000 yards of thread. It’s essential to buy high-quality serger thread, as lint builds up much faster than on your home sewing machine.

Textured Filament Thread: If you’ve ever used “wooly nylon”, then you’ve used textured filament thread. It’s highly elastic and soft. The texture component makes it appear thick and “fluffy” (if that makes any sense). It’s also soft and has a luxurious sheen. It’s commonly used in overlock machines for rolled hems. The thread provides excellent coverage so that the entire raw edge is hidden.

Upholstery Thread: This thread is used when upholstering furniture and comes in a variety of fibers and weights. It’s stronger and more durable than All-Purpose thread. Upholstery thread is available in cotton, nylon, polyester, and silk. Nylon is commonly used because it has some “give”, meaning it won’t break every time someone sits on your reupholstered sofa. Many upholstery enthusiasts recommend matching the upholstery thread fiber with your fabric fiber. For instance, it’s best to use silk thread for silk upholstery fabric. Upholstery thread and Heavy Duty thread are not necessarily the same, although you may see them used interchangeably.

Variegated Thread: This term describes a type of dyeing. The fibers are dyed in intervals of alternating shades and colors along the entire length of the thread. It’s available in a variety of fiber variations and adds a great bit of energy and interest to both decorative stitching and utility stitching.

Waxed Thread: This thread is usually multi-filament and is coated with wax to give it water-repelling qualities. This type of thread is often used in industrial projects, like shoe-making. You may have also heard wax thread referred to as Awl Thread.

Thread Fiber Make Up

Polyester: Polyester thread is synthetic-based and is entirely man-made. It’s low maintenance, durable, long-lasting, and relatively inexpensive. These qualities make it perfect for All Purpose Thread. It doesn’t absorb moisture well and is able to withstand moderate heat. It can easily be engineered to resemble cotton, silk, and even nylon. It doesn’t shrink and can accommodate a small amount of “give” with good recovery. However, it’s a bit more abrasive than cotton and silk (you wouldn’t want to use it on expensive silk chiffon).

Cotton: Cotton is soft, warm, and very absorbent. Cotton thread is derived from the boll of a cotton plant. Each boll contains approximately 250,000 fibers. These fibers, or staples, range in length from short (less than 1 1/8 inches), long (1 1/8 to 1 1/4 inches), and extra-long (1 3/8 to 2 inches). The longer the staple, the less lint it produces. Extra Long Staple Egyptian Cotton thread is considered the gold standard.

Cotton thread is great for sewing other plant-based fabric, like linen, cotton, and rayon.  As long as you are using mercerized cotton, it shouldn’t shrink like your cotton fabric (unless exposed to very high heat). Because it’s highly absorbent, it dyes wonderfully. However, a Cotton thread has no “give” and breaks under high tension, as such, it’s not recommended for stretch fabric.

Rayon: Rayon is plant-based and is known for its beautiful shine and vibrant colors. It’s not as strong as polyester and the manufacturing process is pretty bad for the environment, but it’s inexpensive and comes from a renewable resource (wood pulp). It’s also highly absorbent and fade-resistant. Many people use rayon for their embroidering, topstitching, and monogramming. We don’t recommend Rayon thread for seam construction because it’s not as strong as polyester and becomes even weaker when wet.

Nylon: This synthetic thread is relatively inexpensive and easy to use. It has good elasticity and doesn’t shrink. Nylon melts easily (only use low setting when ironing), especially if it isn’t “bonded’. Bonded Nylon is very strong and comes in a variety of weights. However, it doesn’t hold color well and will yellow over time when exposed to sunlight (unless specially finished with UV-resistant properties).  Bonded nylon is great for utility-type projects, like tool belts, camping equipment, and sports gear.  Pay special attention to how nylon is finished to determine its properties.

Silk: This thread is fine, flexible, and strong. It’s gentle on delicate fabric because it’s not abrasive, nor does it create visible holes. It holds dye well and is known for producing long-lasting, vibrant colors. Silk is washable, lint-free, and comes in a variety of weights. Being an animal-based fiber, it tends to work well with both silk and wool fabric. Silk is often used in fine tailoring, fine embroidery, sewing on buttons, and when finishing the edges of buttonholes.

Wool: This animal-based thread is created from the fleece of sheep and can be spun into fine, medium, and thick weights. Wool thread is commonly used during hand needlework, but specially designed, fine wool threads can be used in machines.  It’s especially useful when embroidering thicker fabric and when you want your design to have great texture.  It also dyes well, creating deep, rich tones. Wool thread is soft, durable, and warm and works wonderfully in the construction of wool clothing and blankets. However, a high-quality wool thread is expensive. Wool will wick away moisture, but once it’s saturated, it loses much of its strength.

Thread Finishes

After the thread has been spun, it needs to be given a “finish”. The purpose of a “finishing” thread is both practical and decorative. By finishing the thread, it’s given protective properties, allowing it to better withstand heat, water, and tension. In addition, many finishes make it easier to pass the thread through the fabric and can create visual effects, such as a silky shine or a soft sheen.

Anti-wick: This finish helps the thread repel water. It prevents “weeping” seams and is resistant to mildew.  It’s also resistant to saltwater damage. You commonly see this thread used in sailing and other outdoor hobbies.

Bonded: Bonded thread has a special resin applied to create a tough, but smooth, protective casing. This is most often applied to nylon and polyester thread with multiple filaments, like corespun polyester and smooth multifilament thread.

Glazed: Thread is coated with wax, starch, and other chemicals to create a glossy, smooth finish. This process protects the thread from breakdown and damage, but it can also gum up your machine. Make sure to frequently clean your machine when using a thread with this type of finish.

Gassed: This type of finish uses high heat to reduce the amount of fuzz and lint created by the thread. This creates a smooth finish and improves performance.

Mercerized: This process coats the yarn, making it stronger and increases its luster. It’s easier to dye and produces beautiful, rich colors. It’s also resistant to mildew. However, it is less absorbent than an unmercerized thread. This process also preshrinks cotton thread.

Unmercerized (soft): The fibers are left untreated and remain in their natural form (relatively speaking, of course). An unmercerized thread is very absorbent, making it more ideal for towels, dishcloths, etc.

Fire Retardant: This thread is able to withstand extreme heat. The special coating is essential for firefighting gear and race car suits. It’s even used in children’s bedding and mattresses.

How Thread is Measured

There are many different ways in which thread is measured and categorized. You’ve probably heard of thread “weight”, but have you also heard of “Tex”? Or seen 40/3 printed on the spool and wondered, “what does that mean?” It’s confusing because different brands will use different measuring methods. Because there is such a lack of consistency and no agreed-upon “industry standard”, thread companies often go by their own rules.

We’ll touch base on the 5 common measurements. However, take all measurements with a grain of salt and use your own experience and judgment.

1.) Thread Weight: How many kilometers of  ‘x’ thread is needed to equal 1 kilogram?

When dealing specifically with weight, the smaller the number, the heavier/thicker the weight. The higher the number, the lighter/finer the thread. So, a thread listed as 30wt is heavier than a thread listed as 50wt because it only takes 30 kilometers (of said thread) to reach 1 kilogram. Most all-purpose sewing machine thread is 40wt. It’s important to note that this measurement is really only used in the US and, again, isn’t 100% accurate, because not all companies actually follow the above formula. Yet, they still label the thread as 40wt. Long story short, some brands borrowed measurements from other brands, not realizing it was an entirely different measurement technique. Oops.

2.) Denier: How many grams do 9000 meters of ‘x’ thread weigh?

You may also see thread measured in Denier. For example, you may see a thread marked as Den 225. This number is saying that the weight of 9000 meters of  ‘x’ thread is equal to 225 grams. The larger the number, the heavier/thicker the thread. The lower the number, the lighter/finer the thread. Most medium-weight thread is Denier 225.

3.) Tex: How many grams do 1000 meters of thread weigh?

This measurement is determined by how much 1000 meters of thread weighs in grams. For instance, if 1000 meters of thread weighs 25 grams, then the thread will be listed as Tex 25. The higher the number, the heavier/thicker the thread. The lower the number, the lighter/finer the thread. Generally,  a medium-weight thread is between Tex 27 and Tex 35.

4.) The Number Standard:

The Number Standard is tricky, I’m still not sure how the numbering is determined. I do know that the lower the number, the thicker the thread. For instance, No. 50 is thicker than No. 100 thread. Make note that No. 100 is not the same as 100wt. It’s like kilometers and miles. They’re completely different forms of measurement.

5.) Composition Labeling:

You may have also seen thread measured as No. 50/2 or No. 30/3. This type of measurement is describing two different characteristics. The first number is meant to convey the thickness/heaviness via the Number Standard. The second value describes the number of plies (strands of yarn) used to create the thread. For instance, No. 50/2 means Number 50 thread composed of 3 plies. Again, this isn’t an exact science. Some companies may use Denier weight or Tex weight in place of the Number Standard.

Now that you know how the thread is weighed, let’s talk about how its strength is determined. There are 4 common methods of testing strength:

Tensile Strength: This is determined by how much force (in grams or kg) is needed to break the thread. A higher tensile strength would indicate a stronger thread because more weight is needed to break it.

Tenacity: This is determined by the maximum tensile force divided by linear density (say what?). The takeaway here is that you want the thread tenacity to match the fabric strength or slightly weaker. The exception is performance products. The thread should always be just as strong or stronger than the fabric.

Loop Strength: This is tested by looping a thread strand through a loop of the same thread and breaking it. This measurement indicates the brittleness of the thread and overall stitch strength.

Knot Strength: This term indicated how much load the thread can withstand when knotted before breaking.

Confused? We don’t blame you. Half of this leaves us scratching our heads. At the end of the day, trust your sewing experience and use what you’ve learned from this guide to determine which thread to choose. We’ll continue to update this as new types of thread are engineered, so be sure to bookmark this article and check back frequently. Happy sewing!

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Joe November 13, 2020 - 2:09 pm

I need to know the diameter of 50 weight, TEX 27 SILK THREAD. cAN YOU HELP ME?
Thank you so much,

S November 4, 2020 - 3:12 pm

I would like to saw elastic fabric by hand with no gatherings and shrinkages, just maintaining the elasticity of the fabric. What strength of elastic thread should I use?

Pamela March 3, 2020 - 7:14 am

Hi there Sarah. What would be the best thread for fireman’s clothing when using a home sewing machine please? I’ve tried several threads and they keep shredding no matter what I do with the tension and using quality needles. Thank you!

Bill Minckler February 4, 2020 - 9:46 am

Sewing Parts Online is insane! 😉 You offer the best research and instruction on so many topics. No wonder I like shopping from your site so much! Thanks.

CustomerService February 6, 2020 - 3:41 pm

Thank you for your kind words and thank you for your business! We appreciate you!

Jan Gaare January 30, 2020 - 4:04 am

Hi, Im a designer and develop gloves for sandblasting. Leather where we use kevlar tread. This works fine, but I have found that someone says the Kevlar tread is cutting into the leather over time, so they use a Dual Duty tread instead. Can someone advice me what would be the best choices. The useage enviroment is the worst you can get.

CustomerService February 7, 2020 - 9:28 am Reply
Annette January 9, 2020 - 11:01 am

The thread stand for cones is amazing!

I was wondering, if you could help me understand what bonded nylon is? And about beading thread, I am feeling lost on this. Beading with seed beads.

Thank you

CustomerService January 15, 2020 - 2:22 pm

Hello Annette! The information that we have on bonded nylon is listed above just below the THREAD FINISHES section; however, if you have additional questions, please call us at 888-824-1192 and we would be happy to discuss your needs.

Octavia McMurray April 3, 2020 - 7:13 am

This article is AWESOME!!! I had been searching for two weeks for information on the difference between embroidery thread and regular thread, but had no idea there were so many types of threads, weights, strengths, cords etc. I love to read so I was happy to find this article with all of this knowledge and so I printed out so I would have it to always be refer back to.

I even contacted a thread company but they did not respond to my voicemail or email messages. 🙁

Love, love, love,
Octavia McMurray

Zachary January 2, 2020 - 5:39 pm

Definitely bookmarked! I came to this guide because I was having trouble with a heavy weight topstitching thread that I was using on jeans. I had to keep turning my tension up and up to prevent looping on the back. I tried it with the same thread on the bobbin and also tried it with lighter weight thread on the bobbin (which did help a little). I was wondering if maybe a spool net would help? Any thoughts about this problem? Thank you so much in advance.

CustomerService January 8, 2020 - 9:02 am

Hello Zachary!

Rather than a spool net, you may benefit more from trying a Thread Stand. I suggest trying something like: https://www.sewingpartsonline.com/thread-stand-alphasew-27449-uth.aspx
I hope this helps.

Marni December 15, 2019 - 9:00 am

Wonderful article! Since I am not crafty AT ALL, and I know next to nothing about sewing, I’m hoping you can help. I want to make a bunch of different edible ornaments for birds and other wildlife, but cannot figure out which thread is ok should deer eat it…. it also would be great to have thread that performs two jobs…. one tip hold the snacks together and the other for the birds to use as nesting material…. any thoughts?

CustomerService December 18, 2019 - 4:28 pm

Hello Marni! Thank you for your kind words; however, I am unable to confidently answer your questions.

We appreciate you taking the time to visit our blog. Have a great day.

Donna February 6, 2020 - 1:46 pm

Thank you for this wonderfully comprehensive guide. I feel much smarter now. But I am still at a loss to find a good black thread for garment sewing. Even with identical metrics as other thread, black always seems thinner and makes a less attractive seam. What’s going on here? Can you recommend a top quality black thread? Both for a standard machine and a serger?

Beth November 15, 2019 - 7:41 pm

Hi! I’ve been reading for the past hour and a half and this is the best website explaining threads. I can stop reading now 🙂 as there is so much information to take in I will have to read it again tomorrow. I’m always thankful to those who put in the effort to explain things in the easiest possible way.

CustomerService November 19, 2019 - 4:31 pm

I am so glad you are enjoying it!

Debra DeCordova October 28, 2019 - 7:45 pm

My problem is that I cannot find any numbers on the spool to indicate the weight of the thread.
It is Coats & Clark S974 E9 8145 Dual Duty Plus for jeans top stitching. I find lots of info about thread weights, but where is the number on the spool?

CustomerService October 30, 2019 - 11:03 am

Hello Debra!

I have been unable to pull up information on our site for the particular thread you are using; however, if you can email us some pictures of what you have, we will be happy to look into this for you. Our email is info@sewingpartsonline.com.

Kirsten September 10, 2019 - 5:04 pm

Hi there, I’m looking to make my own Dutch style face wash cloths and accompanying hand towels using towels that I have. Is it alright to use polyester thread, or should I stick with a cotton type thread? I can’t see that the pull on the fabric would be extreme under normal use. Any advice would be greatly appreciated.

CustomerService September 27, 2019 - 8:25 am

Hello Kirsten!
I am sorry, but I do not have any information on this particular project. If you could call us; we can discuss details and see if we have any suggestions. We can be reached at 888-824-1192.

Singer December 15, 2020 - 5:09 pm

I bought 20S/2 All Purpose Sewing Thread Spun Polyester Overlock Cone 1500 Yards Sewing Thread , to be able to use more economical, larger cones if thread for my projects than the small spools, in my Singer 301a sewing machine. My machine has been sewing great with regular gutermann 100% polyester 500m & 1000m spoolsbof thread.
But immediately when trying to use the cone of thread I bought it tangles, knots and jams in my machine! I’ve tried putting cone behind, above & and tonside, above & straight behind machine, nothing is changing it. It tangles a mess below the plate. I’m using regular gutermann thread in bobbin. This polyester overclock cone seems thicker.
How can I get it to work reliably, smoothly in my singer 301a sewing machine?

CustomerService December 16, 2020 - 8:32 am


You will not be able to use the overlock thread in your sewing machine at all. It will bunch up and break no matter what you do. If you are looking for a larger spool of thread to use Fil-Tec, Glide 40wt Trilobal Polyester Thread (5460yds). I hope this information helps!

Timothy September 1, 2019 - 8:35 pm

I am wondering what cotton #10 crochet thread is in thickness compared to poleyster thread, i.e., the weight, like is it 40 weight?

CustomerService September 18, 2019 - 9:53 am

Hi Timothy!

I apologize; I have been unable to locate the requested information.

James Calhoun July 3, 2019 - 4:56 pm

Sarah, thanks so much for an informative article. I am a complete beginner in sewing and trying to understand thread. My project is to add a hem to some tartan cloth I got from a mill in Scotland. It has a raw edge and to prevent it unraveling would like to hem it. The tartan is heavy weight 16 ounce tartan cloth. The sewing machine Is a Brother CS6000i. You can email with any recommendations of threads you have on your website if that is easier. Thank you for you consideration.

CustomerService July 9, 2019 - 10:54 am

Hello James!

As I have not sewn on this specific material, I am unable to speak from experience; however, after some research online, there were suggestions for both cotton and polyester. I have provided links to options that we offer in these categories:

Cotton: https://www.sewingpartsonline.com/sewing-and-serger-thread.aspx?filter.fabricmaterial=Egyptian%20Cotton&filter.fabricmaterial=Cotton
Polyester: https://www.sewingpartsonline.com/sewing-and-serger-thread.aspx?filter.fabricmaterial=Polyester&sort.ss_cat_sort=desc&index=1

I hope this helps.

Nidhi April 28, 2019 - 9:35 pm

I’m looking for natural decomposible thread so cotton seems to be my only option. I want to use it for cotton canvas bags so can you suggest the strongest cotton thread available for heavy fabrics. Thanks

CustomerService May 1, 2019 - 4:09 pm

I believe a good option for you to try would be:
This is 100% natural cotton Gutermann Thread and it is 50WT.

Amanda April 16, 2019 - 4:07 pm

Hi Sarah, thanks for the great information. I am sewing thick fleece material to 100% cotton sheets to use on a bed. It has to take many washings. What type of thread would you recommend. I find that the fleece is somewhat stretchy and the cotton sheet is not so I’m trying to figure out the best thread type.

CustomerService April 22, 2019 - 9:32 am

Polyester All Purpose thread is your best choice. It’s strong and resilient enough to hold up to the weight of fleece and to accommodate fleece’s “give”.

anch April 9, 2019 - 7:21 pm

This is really interesting, You’re a very professional blogger.
I’ve joined your rss feed and look forward to in the hunt for
extra of your great post. Additionally, I’ve
shared your web site in my social networks

Sue March 28, 2019 - 2:07 pm

Wow. Your article has so much information. I need a natural thread to use on thick cotton webbing and needs to withstand tension. What do you recommend? Thank you!!

Julie March 14, 2019 - 2:10 pm

I need to alter some swim wear and spandex athletic clothing and don’t know what thread to use. I have seen some sites say Wooly Nylon but I’m not sure. Can you please help?

CustomerService March 15, 2019 - 2:20 pm

Hello Julie! By doing some research, it appears that a good thread to use is coats and clark Dual Duty XP Thread. You can view that thread below:


Heather March 8, 2019 - 12:38 am

Hi, I’m sewing some buttons onto sofa cushions to keep them from slouching, I’m not really very experienced in any of this. However, I’ve already done this once before, and it looked like it turned out fantastically, but, a few months later the thread I used broke and so, the buttons came off. So, I’m wondering if I should use industrial thread? Any advice would be greatly appreciated. Thank you. 🙂

Yvonne March 4, 2019 - 12:14 am

this has been a fascinating read. My request is for guidance with sewing 100% cotton fabric that will be sterilized. I am making surgical sheets to go overseas. I would like them to last as long as possible. Would you recommend cotton or polyester thread?

CustomerService March 6, 2019 - 1:23 pm

Hello Yvonne! We recommend using polyester thread since it is more durable. I hope this helps!

Rosemarie February 21, 2019 - 9:07 am

Hello there, You have done a great job. I will certainly digg it and personally recommend to my friends.

I am sure they will be benefited from this site.

Deborah J Stasse January 21, 2019 - 12:52 pm

Thread Mastery: A Guide to Understanding Threads by Sarah is wonderful! Have you considered publishing it as a booklet? Perhaps it could be coupled with ‘understanding needles’?

CustomerService January 21, 2019 - 4:26 pm

Hello Deborah! We appreciate your suggestions! We might publish a book in the future. As for the needles, we do have a blog on the correct needle to use and a chart. That can be viewed via the link below:


Moni January 19, 2019 - 9:39 am

Hi, I am planning on mending a chiffon dress. Was wondering what is the best thread to use. Thinking something thin Clear Thread or embroidery thread? Not sure, just need thin in order to closely blend and not stand out too much when mending a tear. I know mending chiffon is difficult but want to try with the right thread.

CustomerService January 21, 2019 - 4:20 pm

Hello Moni! I would suggest using the Dual Duty XP Fine Thread. You can view that thread below:


Dina January 3, 2019 - 5:37 pm

Hello – I just bought a small lot of “vintage” threads which included some labeled as silk. A few other didn’t have labels and I was wondering how I can determine if those were silk as well. Thank you!

CustomerService January 4, 2019 - 2:46 pm

I am sorry, but we would not be able to advise on that. The best that I can suggest is to compare the thread that is labeled to the thread that is not labeled to see if they are the same. I wish I had more information for you. I am sorry I could not be of further assistance.

Deborah J Stasse January 21, 2019 - 12:49 pm

The only way I’ve found to test if a thread is silk is by burning a piece and smelling it! If it smells like burnt hair, it’s silk. Somewhat subjective, but other than having a chemistry lab at your disposal, that’s the only way I know of.

Pitt Chao January 1, 2019 - 9:10 pm

Yarn Twist Tester, to determine yarn twist in single or plied yarns, quadrant type with auto stop & reverse for conventional or untwist/re-twist methods. Twist Tester Machine complies with ISO 2061, ASTM D1422/1423, BS 2085, etc.

Jason December 18, 2018 - 12:55 pm

I’m new to this so please forgive the remedial question, but if I’m hand tailoring a men’s wool suit what kind of thread do I use? Silk? Cotton? Polyester? I can’t seem to find a basic answer to this question anywhere.

CustomerService January 2, 2019 - 12:49 pm

Hi Jason! I would recommend sewing with Polyester thread on the wool suit since that would be a more durable thread. I hope this helps!

Aman September 16, 2018 - 2:38 pm

which counts of polyester thread is used in stitching a women shirt dress generally?

CustomerService September 19, 2018 - 12:20 pm

A 30 or 35 wt should work well for your project. If you would like to use a polyester thread, I recommend the Dual Duty XP thread. You can view available colors via the link:

Pitt Chao September 11, 2018 - 1:04 am

Thanks for your sharing. Fabric density refers to the number of yarns per unit area of the fabric. Fabric Density Meter used to test the number of yarn of all fabrics. For more information, please click on https://www.testextextile.com/product/fabric-density-glass-tf122/

Kelly March 21, 2018 - 6:34 am

Hi Sarah,

I have a sewing workroom. I have a new job in hand and a little nervous about starting it. The fabric is sheer that is very expensive and I am sewing with an industrial machine. What TEX thread do you recommend?

CustomerService April 27, 2018 - 10:27 am

Hello Kelly! I would recommend going with Tex 9 to Tex 20 for very light sheer fabric. Starting off with around Tex 9 would be best. I hope this helps!

Anna February 17, 2018 - 8:13 pm

Hi Sarah, thank you for summarizing everything so nicely on one page and thank you for taking time to answer so many questions. I have a question. I wanted to join silk charmeuse fabric remnants side by side by flat lock serger seam to make a nice patched scarf. I know this is a tedious project for very careful people 😉 but still want to try as I have tons of matching pieces of charmeuse. The final seam would contain two pieces flash side by side locked together by a single overlock which will simultaneously prevent unraveling and join them together.

What would you recommend as a thread for doing this flat lock stitch? I was thinking embroidery thread with high sheen and strong enough… May be rayon 2 ply 40? Please let me know what you recommend

Thank you

Sarah February 20, 2018 - 10:15 am

Hi! I think that or a wooly nylon would work well.

Irene Hough February 16, 2018 - 3:16 pm

I would like to make those Microwavable pot holders for bowls . The patterns I have found on Pinterest all call for 100% cotton thread (not polyester covered). I went to my local Joanne Fabrics but there are so many to choose from and none specifically states “microwave safe”. Is mercerized thread safe? What specific brand thread would you recommend. Thank you.

Sarah February 19, 2018 - 2:15 pm Reply
Katie February 7, 2018 - 10:15 am

what TEX would you suggest to use on a glove liner using 66% MODACRYLIC / 29% RAYON / 5% SPANDEX

Sarah February 16, 2018 - 1:52 pm

That is a tough one – what is the weight of your fabric?

Linda January 24, 2018 - 10:32 am

Very interesting; do you have any thoughts about whether to use cotton or polyester thread when doing patchwork using cotton fabric. I know traditionally cotton thread was recommended, but that dates back to before modern synthetics. I’d love to see some scientific evidence either way!

Sarah January 30, 2018 - 9:07 am

Hi! Most people prefer to use cotton thread when sewing 100% cotton fabric.

ED November 28, 2018 - 3:26 pm

There is absolutely no possible chance of “scientific evidence either way”. It really doesn’t matter what thread you use – it is up to you & your personal preferences for that particular piece of work at that particular time…..and you can mix and match and change your mind as much as you like. Look what the best free motion practitioners achieve by using anything and everything. Any preferences should be personal. If anyone thinks they have “rules or best practice ” they really have imagined them. The only thing to watch is that the thread is strong enough for your thickest work – which it probably will be. If you need a stronger thread your machine will let you know at the time.

Uzodimma January 23, 2018 - 1:01 pm

Hi Sarah, i want to sew a shirt. which of these size of thread will be best for it NE 30s/2, NE 40s/2 and 60/3

Sarah February 5, 2018 - 10:14 am

Of those three, I would say the 40/2. You would definitely need to reinforce the high-stress areas.

diane bruni January 13, 2018 - 3:36 pm

Hi, I am creating a resistance band for exercise, it is made of wover elastic, the type used for parachutes, its very resilient, I am attching velcro to hold the ends together. What tyoe fo thread will rpovide the most strength and give, it needs to stretch with the elastic. Thank you,

Sarah January 17, 2018 - 10:38 am Reply
Cindy December 27, 2017 - 11:20 am

I googled, “Which is stonger, upholstery thread, or button thread?” and I ended up here. The info was all fascinating, but I’m not sure that my question was answered. So, which do you think? I’m planning in using it for stringing beads, and knot the two ends together, thus doubling the strength.

Sarah December 29, 2017 - 2:12 pm

Hi! It depends on the size/weight of your beads. I would use Upholstery Thread. I’ve had good luck using monofilament (clear) thread for beading projects. For long strings of large, heavy beads I would use Bonded Nylon thread.

Jenny December 25, 2017 - 5:04 pm

Hi Sarah. I am an amateur to sewing. I have a horse that keeps breaking her nylon leg straps off her winter blanket. I end up having to send it for repair several times in one winter. I am thinking I could sew them myself which would save me some money and time. The nylon leg strap itself is not breaking, it’s where it is being sown on the blanket that does not seem to hold up. It keeps coming apart. Could you recommend a thread and a type of needle that would help me and could this be done by hand, as I do not own a sewing machine? Thanks in advance.

Sarah December 29, 2017 - 2:03 pm

Hi, Jenny! The area where the strap is attached to the blanket needs to be reinforced. Mark where you want the strap to attach to the blanket. On the back of the blanket (where you marked) stabilize the fabric with a large piece of iron-on medium stabilizer or an iron on patch. Set aside.
Then, grab a scrap piece of lightweight leather, vinyl, or medium denim. Cut it into a square that is 1/2″ bigger than your nylon strap on all sides. Sew the nylon strap to the square piece making a box and X pattern (use an upholstery needle and heavy-duty polyester or bonded nylon thread). Position this piece on to the blanket (where you marked, opposite side of the iron on stabilizer patch) and stitch a 1/4″ seam around all edges of the square so that the leather square is sewn to both the blanket and the stabilizer patch. Be sure to back stitch and secure the thread tails. You might even want to go over the ends of the stitch with a seam sealant glue.

Jeri Haney December 6, 2017 - 6:35 pm

High there Sarah. Have kind of peculiar question. We have rescued bunnies, they are litter box trained (but sometimes accidents happen), and I would like to make trays from canvas to sit under litter box that can be switched out every couple days. Need to a water proof seems as best a possible. Looked into spray on/paint on stuff but don’t like chemicals. Hoping there is a thread that can help. Planning on frenching seems to help. Thanks for any help you can give.

Sarah December 8, 2017 - 2:00 pm Reply
Antonia Niki October 7, 2017 - 12:50 pm

Hi Sarah,
My name is Antonia. I’m from the Commonwealth of Northern Mariana Islands (Saipan). We are part of United States.. I am not sure if you know our state but I’m really hoping that you do, if not maybe you can goggle ” Commonwealth Northern Mariana Islands ” I’m sure you can find us. Our neighbouring island is Guam USA.. I’m interested to order some thread, my question is, can it be shipped to our island? Please let me know. Thank you very much in advance!

Sarah October 9, 2017 - 4:44 pm

Hi! I believe we can. If you have any trouble placing your order, please give us a call or email us: https://www.sewingpartsonline.com/contact-us.aspx

Phyllis September 14, 2017 - 9:23 pm

Great information, thank you. I do a lot of machine embroidery and wanted to know if polyester thread shrinks.

Sarah September 15, 2017 - 9:28 am

It sure doesn’t!

Charlie Harding August 29, 2017 - 5:17 pm

HI. That iinfo on thread was very interesting, But when you have a sack full of threads from yard sales, un marked, how do you sort them??
Love Charlie

Sarah August 30, 2017 - 8:53 am

Hi, Charlie! That is a common problem. You can determine the fiber content via a burn test. You’ll have the evaluate the weight/thickness by assessing the best you can and comparing to other thread you have.

Tim Morris March 28, 2021 - 11:45 am

We’re looking for specs on Vicar’s Vylon threads. Where can we get those?

Margaret August 14, 2017 - 12:42 pm

Wow, loved the read on threads.
I too will print so that I may defer to it often and not have to rember all.
Thank you so very much for this info.

Sarah August 14, 2017 - 3:22 pm

Our pleasure!

Kathleen Boggess August 14, 2017 - 11:07 am

Great article and the timing is perfect. I’m scheduled to do a short presentation to my quilt group on threads including specialty threads like elastic, wash away and fusible. I’m starting with the basics so this information really helps. Thank you.

Sarah August 14, 2017 - 3:22 pm

My pleasure! So glad to help!

Patty August 14, 2017 - 8:30 am

Oh my. What a great article this is. I’m going to print it so I have it handy. Thank you for sharing all your hard work, Sarah.

Sarah August 14, 2017 - 9:53 am

My pleasure! Thank you for your kind words!

Lois Borton August 13, 2017 - 10:34 am

What great, knowledgeable,informative and most welcomed lesson on threads.
Thank you for sharing and helping us understand this.
Lois B

Sarah August 14, 2017 - 9:54 am

My pleasure! Thank you for reading!

Kathleen Steimle-Hermes August 12, 2017 - 1:52 pm

Great and comprehensive article. Would have been even better had it been made so it could have been downloaded as a pdf document. I like to print out things like this and store them in sheet protectors in notebooks to refer to them.

Sarah August 14, 2017 - 9:56 am

Excellent suggestion! We are currently working on making this a downloadable pdf.

Margaret Hayter August 16, 2017 - 2:10 pm

That would be great. Please send out an email blast to us when it is done. This info is superbly done. Thank you.

Sarah August 17, 2017 - 8:28 am

I’m working on it this week!

JOY August 12, 2017 - 1:43 pm


Sarah August 14, 2017 - 9:57 am

It drove me crazy for years, too! I’m so glad it was helpful – thank you for reading!

Charlie Harding August 12, 2017 - 8:38 am

Hi Sarah, This is all very technical and interesting, but, I have a box full of used reels, how do I sort them out??
Regards Charlie

Sarah August 14, 2017 - 10:18 am

Hi, Charlie! Do the spools have any information stamped on them?

Kayte August 12, 2017 - 8:35 am

Wonderful article! People know I sew and ask me questions about things like thread types. When I begin a description of how there are different types for different projects, they sort of glaze over. I am going to save this article and share it as a gift.

Thank you!

Sarah August 14, 2017 - 9:55 am

Thank you so much!

Edward Best August 11, 2017 - 3:03 pm

Hi Sarah,
What type of lay-on (decorative) thread is used on the industrial smocking machine.


Sarah August 11, 2017 - 3:45 pm

Hi, Edward! From what I’ve read, high-quality “embroidery” thread is most commonly used. I’m finding that polyester embroidery thread is preferred because it’s stronger.

Linda B August 11, 2017 - 9:44 am

Sarah…this is so lovely and timely. Thank you so much for putting this together. I need to cut and resew some shade cloth and had no idea that there was such a thing as UV resistant thread. Do you carry it in Heavy Duty? And maybe with anti-wick properties? Like others, I have enjoyed and appreciated your tutorials.

Sarah August 11, 2017 - 1:07 pm

Hi, Linda! Thank you for reading our article- we appreciate your support!
We have two thread brands that would work for what you need:
Coats and Clark Outdoor Thread: https://goo.gl/Sw5C6q
Fil-Tec Thread: https://goo.gl/gxMhjT

Patricia May 12, 2017 - 10:52 am

What thread would you recommend for hand-sewing wool rugs? I would like it to be biodegradable if possible.

Sarah May 12, 2017 - 11:16 am

Hi, Patricia! You would definitely want to use a heavyweight wool thread. We don’t currently sell that kind of thread/yarn, but Aurifil may have something you can use.

Leslie March 29, 2017 - 8:22 pm

Sarah, very comprehensive article! Thanks for including so many thread types and characteristics. My inner sewist was reawakened by a purchase of an ancient, but still sturdy and serviceable Husqvarna with pattern seam “formers”. I fell in love with embroidery for the first time. Naturally, now I need the right threads (and needles). This helps me understand a lot more. I also wanted to mention I’ve watched some of your videos and I am thrilled with the accurate captioning. Without this, all your instructions would be inaccessible, but with it, I can learn and review without problems. Keep up the good work!

Sarah April 3, 2017 - 9:33 am

Thank you for your kind words!

Marta March 28, 2017 - 2:33 pm

I grew up in the South where cotton is grown. I never heard of cotton “bull”. I was wondering whether this a misunderstanding of the word “boll” or just a typing accident. Cotton boll is the term for the chunk of cotton picked from its growth place on the plant. To reiterate: cotton BOLL. If you have information as to the origin of “bull” please inform me. I don’t want to be ignorant. Thank you.

Sarah March 29, 2017 - 4:41 pm

Hi, Marta! Nope, you are correct! I accidently used a ‘u’ instead of an ‘o’. Sharp eye!

Lan Kazimierz March 19, 2017 - 10:24 am

Need some thread

Sarah March 22, 2017 - 9:01 am Reply
Lan Kazimierz March 19, 2017 - 10:17 am

Need some thread black. Gold. White. Blue red.purp

Sarah March 22, 2017 - 9:00 am Reply
Lan Kazimierz March 19, 2017 - 10:04 am

Brake the top thread

G.J.P.SUSANTHA FERNANDO March 8, 2017 - 6:32 pm


Sarah March 9, 2017 - 10:44 am

Hi! We sell many different types of thread here: https://goo.gl/Hw62qp
Simply “Add to Cart” and when you’re finished, click on the “Shopping Cart” located in the top right-hand corner of your screen.


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