weaving thread sizes?

Can someone please help me understand what I am looking at when I see a weaving thread size?  And then what the different sizes are so i know how or what to choose to plan a weaving project?


Posted on Wed, 09/28/2011 - 19:45

 Cotton is sized like so: a number 1 cotton contains 840 yards and weights 1 pound. ex. 3/2 What you have is (2) two strands of number 3 cotton. # 3 cotton is 840 x 3 equals 2520/2 or 1260 yarns per pound. Again using 10/2, 10 x 840= 8400/2= 4200 yards per pounds Hope this helps. Yes in Canada they put the number of plys first them the size of the yarn. They also do the day/month/year. Then we have the metric system…..


mercerization is a treatment for cotton fabric and thread that gives fabric or yarns a lustrous appearance and strengthens them. You can find more information here: http://www.ask.com/wiki/Mercerised_cotton

This is only for cotton, you have a system for wool, linen etc You can find the informations on other yarns here: http://www.sizes.com/units/yarn_numbers.htm



Posted on Mon, 01/09/2012 - 22:28

Just to clarify....

For most weaving yarns you'll see two numbers, such as 5/2.  One respresents the number of twists per inch in the yarn, the other is the ply--so, our example yarn is two ply yarn with five twists per inch.  Unfortunately, this is a really irregular way to size yarn--I've found that different fibers may have the same number size, but a 5/2 in cotton may be smaller than a 5/2 in linen.  Still, it does make it easier to remember what you bought.

So, how do you know what size to get?  Look at the epi (ends per inch).  Most good weaving suppliers (like The Woolery) will have an epi listed by the yarn in it's description.  It's also usually a range, such as 24-30 epi.  If you're super new to weaving, epi is simply the number of threads laid side by side to cover an inch.  So, the bigger the epi, the finer your fabric.  This is one rule that holds true no matter what fiber you're using.  It's also great if you have a limited number of reeds and can't quite get the knack of alternate threading sequences (guilty).  That way, if all you have is a 10 dent reed, you know you can easily thread yarns with 10, 20, 30, 40 (and beyond!) epi.


Posted on Mon, 01/09/2012 - 22:50

Excuse me, but yarn numbering systems do NOT refer to twists per inch.

5/2 cotton means that the yards in a pound are equal to 5 hanks of 840 yards divided by the two plies.

Every new weaver really needs to get a good book that gives charts on the various yarn numbering systems - Big Book of Weaving has good ones, there is something out there with facts for weavers from a guild, Interweave has that Weavers Companion spiral reference guide.

There are the old English numbers - 840 yards per hank for cotton, 300 yards per lea for linen, etc. 16/2 linen is 16 300 yard leas for 4800 yards per pound in the single, divided by 2 for 2400 yards per pound.

Metric numbering is where the first number is meters per kilogram divided by the number of plies. a metric 20/2 worsted would be 20,000 yards per kilo divided by 2 for 10,000 meters per kilogram - or 5,000 per half kilo which is about a pound.

Twists and actual thickness of the yarn cannot be measured from the numbering systems - the numbers are there for  calculating yarn needs for a project.

And Linda R. you're sort of on the right track, but should really become a bit more knowledgeable before throwing out blanket advice that is not accurate.

Posted on Tue, 01/10/2012 - 02:19

I stand corrected.  That is what I was taught. 

It has been my experience that epi is a more useful indicator of a yarn's thickness.  I was simply trying to provide a little assistance to make yarn selection simpler.



Posted on Tue, 01/10/2012 - 03:13

Figuring out yards per pound (or meters per kilo) is a bit of a challenge because not only do the different fibres have different values for a number 1 size, there are also different numbering systems.

You have to know the value for 1 plus you have to know if the system you are using uses that value.

As Michael says, the value for a size 1 in cotton is 840 yards per pound (approximately).  In Canada our standard cotton size is 2/8, while in the US their standard is 8/2.  Now you might think that the two countries have simply reversed the number order, but the 2/8 cotton I'm familiar with is very different from the US 8/2.  They are completely different yarns, partly because I think one has been combed, the other carded, and then - although I haven't actually counted the number of twists per inch, I believe the US 8/2 cotton has fewer twists per inch than the Canadian 2/8.  One of these days I must sit down with a magnifying glass and count them, I guess.  :)

So yes, yarn sizing/numbering is definitely confusing!

Unfortunately in none of the numbering systems I am familiar with is the number of twists per inch indicated, even though this would be a useful thing to know at times.  Certainly a yarn with more twists per inch than exactly the same grist (or thickness) with fewer twists per inch will behave quite differently.



Posted on Tue, 01/10/2012 - 12:25

Yarn twist, direction of twist and the amount of twist is set by the manufacturer and it's customers. There is no international standard for twist. Twist is the number of turns per unit lenght. Then we have "S" and "Z" twist which tells the direction of the twist. (simple ans) Then there is open ended and ring spun yarns, carded and combed? We can spend the next week writing about the types of dyes and dyeing.

For the weaver/spinner the easiest way to figure the lenght of yarn per weight is using a McMorran yarn balance: http://allfiberarts.com/2011/aa022800.htm




Posted on Tue, 01/10/2012 - 14:40

Great question, a variety of responses, and THIS is why I am SO glad we have Weavolution! Now that the technical end of things have been addressed, I am going to try and take the easier, low-tech approach to my answer...

The numbers 3/2, 5/2, or 20/2 tells me the grist/diameter. In America, the larger the first number, the finer the yarn. Some folks think 20/2 looks like sewing thread. An average sett for 20/2 in plain weave might be 36 ends per inch (e.p.i.).

A lot of beginners like to start with 3/2 or 5/2 because it is an easy thread size to handle and we won't have to sley it so densely. An average sett for 5/2 in plain weave can be 18 e.p.i.

Another other key way for me to look at weaving yarn is by "yards per pound", or ypp. The larger the number, the finer the yarn. 5/2 is 2,000 ypp, and 20/2 is 8,000 yards per pound.

For garments (including scarves) I would try anything from 8/2, 10/2, 16/2, 20/2 or higher. The higher number you go, the finer and lighter drape the fabric will have. Make that silk, bamboo, or tencel instead of cotton, and the drape improves even more.

For towels, weavers use anything from 5/2 to 16/2. The 5/2 gives you a pots 'n pans towel, the 16/2 would be nice for your glassware. 

For baby blankets, one of my favorite yarns is 1,100 ypp, and the sett is 8-10 e.p.i.

If you have a mystery cone or skein on the shelf, Michael's link to the McMorran Yarn balance is great. This tool helps you figure out the yards per pound, so you can then figure out your sett.

I like to stick with weaving-specific vendors for my weaving yarns. Folks like Halcyon make it easy to see this information on their site when looking at their weaving yarns. "Lace weight", "Sport" and all those knitter's labels really don't tell me specifically what I need to know about a yarn.

And if you spin (I see your avatar is a spinning wheel!), you know knitting yarns just aren't spun as for weaving. Yes, we CAN weave with knitting yarns, but I don't find it nearly as enjoyable as working with yarns designed for weaving that go on the loom like butter!

Why not set up a little sampler for yourself? Try a few different size wefts and see what happens to the resulting fabric? 


Posted on Sat, 03/10/2012 - 22:42

I'm very new to weaving on anything other than my inkle loom. I ordered a bunch of white and colored yarn in 8/2 cotton, but the white has been backordered, and won't be in for 4-6 weeks. I do have quite a bit of cotton crochet thread. Does anyone know what size crochet thread would be similar to 8/2 weight?

I had planned on placemats for my first warp, with accents of different colors, so without the white I can't even start my project.

Posted on Sun, 09/22/2013 - 12:10

Crochet cotton is 10/2 mercerized. I find it to be a little finer sett, around  22-24 epi in twill than 8/2, which can be around 20-22 epi. This depends on the complexity of the twill.

Posted on Mon, 09/23/2013 - 05:36

crochet cotton thread come in sizes 3, 5, 10, 20, 30, 40 etc up to 100.

I doubt they are all equivalent to 10/2.

Posted on Mon, 09/23/2013 - 08:54

Sorry, but I only see 10/2 available in Walmart, so my mistake. There are two brands they carry and all 10/2 cotton. Also Mardens carries it in unlabled bags, don't know the maker, but from India. Also 10/2 only. But regardless of that blunder, I am only comparing 10/2 with 8/2 cotton here and not any other sizes.

Posted on Tue, 09/24/2013 - 16:44

Hi all,

I found some old say 30 or 40 years old wooden stick suttles Pine maybe (my estimation only..could be older)...that are plain wood but most likely had some redish stain put on them at some time in the past.  I have sanded them down a bit now I would like to know what finish i might apply? Could I use Paste wax safely ?? I'm not at all knowlageable about wood working ..need help please!

Posted on Thu, 09/26/2013 - 05:14

The standard crochet cotton I've seen is 10/3, not 10/2. The packaging just says #10 cotton. 

Posted on Thu, 09/26/2013 - 09:23

Dianne, I had to get the magnifier out and look. And you are right, it is 3 ply #10. It still takes a sett I described above, I've used it many times in weaving.

Posted on Thu, 09/26/2013 - 22:45

The best thing to do is get color cards, they have samples of the yarn on it.  You can see the true color and size, feel it and compare it.  They cost a little bit of money, but when you're planing a project, they're a great go-to resource. Just do yourself a favor and retape them if they seem loose, and keep them in a three ring binder or they get all messed up.  Buying one wrong cone costs more than all the color cards you would buy.  Just my opinion.

Posted on Mon, 08/11/2014 - 21:47

What size reed do you have? What do you intend to make with this yarn? 8/4 is thicker yarn than I use for warp unless I want to weave a rag rug, but some people like it for sturdy bags or place mats. When I choose the yarn for my next warp, I have some end products in mind. I think about the design I want and the weave structure that would be best. Then I can figure out the appropriate sett (number of warp ends per inch = epi) for that warp. Say you wanted to make something using 8/4 for both warp and weft. Maybe you know about plain weave and twill. Which would be better? Plain weave is a thinner cloth and it uses less yarn, while twill has more drape and is thicker and warmer and more durable generally. Would you want to see more of the warp, or more weft, or equal amounts of both (balanced weave)? Next you can read about the chosen weave structure and you can look up a yarn sett chart in a book or online to see what is recommended for 8/4 for balanced plain weave or balanced twill. Adjust the sett for cloth that is not balanced.

Then you figure out how many threads to put in each dent in the reed you own, to get the right epi. You might want a sett of 12 epi. You can do this with a 6-dent reed (2 per dent, often a good idea) or a 12-dent reed of course, or an 8-dent (1/2/1/2/1/2/1/2) or 10-dent, etc. But a thick yarn like 8/4 will not work in a fine-dent reed (15 or highter).

It will help a lot if you can take a beginning weaving class in person or online, or work with a book for beginning weaving. This forum is not going to take the place of a class, I'm afraid.

Bonnie Inouye

Posted on Fri, 08/15/2014 - 00:21

I find Warp Weft Sett by June Beveridge immensely useful.  It has the pictures you expect from the title, with different yarns at different setts in twill and plain weave.  Basically, it's just a lot of pictures of samples and a table or two.  You can get it used on Amazon for less than $10 American.

Posted on Sat, 11/18/2017 - 21:09

Could someone provide a comparison between the tex system and the system that has just been discussed for weaving yarns.  I am reviewing a catalog from a company that supplies tailors and the sewing industry as I consider using their threads for weaving.  Tex is shown charted for their threads between 8 and 400.  And there may be a specific tex range for each fiber type in the makeup of the "thread."  e.g. polyester, cotton, silk, nylon, etc.



Posted on Sat, 11/18/2017 - 21:09

Could someone provide a comparison between the tex system and the system that has just been discussed for weaving yarns.  I am reviewing a catalog from a company that supplies tailors and the sewing industry as I consider using their threads for weaving.  Tex is shown charted for their threads between 8 and 400.  And there may be a specific tex range for each fiber type in the makeup of the "thread."  e.g. polyester, cotton, silk, nylon, etc.



Posted on Sun, 11/19/2017 - 09:28


"A unit indicating the fineness of yarn: the mass in grams of a 1-kilometer length of the yarn. Unlike most yarn number systems, this one was intended to be applied to every type of fiber, internationally. See yarn numbers for a comparison with other systems. Symbol, tex."