Confused by Thread sizes?

Thread sizes can be almost as confusing as dress sizes! Part of the confusion comes because there are different sizing systems used. For most of our threads, rather than put a numerical weight or size on the label, we use a descriptive term such as Machine Quilting, Upholstery, Fine, All-purpose or Heavy.

We would like to try to clear up some of the confusion about thread size. Thread sizes are based either on a fixed weight system or a fixed length system.

Fixed weight systems describe the length of thread needed to weigh a specific amount. In these systems, the higher the number, the finer the thread. Two systems are the Cotton count which is based on 840 hanks =1 lb and Thread weight based on 30 meters = 1 gram.

Fixed Length systems use the weight of a given length of thread. In these systems the higher the number the larger the thread. Two examples are Tex which is the weight in grams of 1000 meters and Denier which is the weight in grams of 9000 meters.

Then there is size… This is an older system that groups threads into fine (Size 60), medium (Size 50) and heavy (Size 20) categories, with again, the higher number being the finer thread.

For an in-depth explanation of thread size, read Unraveling The Mystery of Thread Size by Ken Nelson, Sr. Product Manager-Sewing Thread, Coats & Clark.

This chart gives the Tex and Weight for Coats threads.

Coats Threads Tex and Weight Chart


20 thoughts on “Confused by Thread sizes?

  1. Leebeloola Reply

    Thank you so much for the thread chart. I’m new to sewing and having gathered most of my supplies from other people I have no idea what each thread is good for. The jeans one I found most useful as I have had some problems with using too strong thread on jeans patches only to find that it can get a bit itchy.

  2. Lynn Browne Reply

    The size system used in this article is Tex which is based on Fixed Length which is based on the weight of a fixed length of thread. In this type of thread size system (which is typically used in industry) the larger the number the larger the thread.

  3. Anonymous Reply

    Please help!
    i’m looking for coats and clark “summer brown “
    with a .210 dia
    i’ve only seen threads measured by thread weight. What is the thread weight of that .210 dia?

  4. Anonymous Reply

    I am researching a project and came across a reference to 20/4 cotton thread. Could someone please explain “20/4”???


    • Lynn Browne Reply

      This is explained in the article Unraveling the Mystery of thread size. There is a link in the blog. 20/4 means the thread has 4 plies and each ply is a Ne 20.

  5. Chip Davis Reply

    Hello Lynn, I read the article but there is no chart now.

    Trying to figure out if the Coats & Clark Dual Duty XP All Purpose thread I have purchased would be good for Fishing Rod building which calls for thread size A ? Thanks

    • lynnbrowne Post authorReply

      We do not have a chart that gives specific thread strength. The description of the thread indicates the appropriate use. For more specific information please submit a request via ‘contact us’ on

  6. Amanda Reply

    The chart seems to be missing from this blog post. I put together a sewing thread size chart that’s free to download on my blog if it’s helpful to Lynn or other readers. It includes common conversions, conversion formulas and recommended thread sizes for different fabrics.

  7. Barbara Williams Reply

    I have older spools of Coats and Clark thread which do not have a wt. size printed on them. What size are they? They just say all purpose thread.

    • lynnbrowne Post authorReply

      If the spools are Dual Duty Plus, a cotton-wrapped polyester, they are 35 weight. If you have more questions about the spools go to and use the “contact us” link.

  8. Name *Vivian Reply

    I have confusing, Buyer said that we need use tex240, but I don’t know what is tex240? it’s 30s/3 or 60s/3? could you advise to me? – thanks.

  9. rosalinda solis Reply

    i also couldnt see chart but would like one i buy

    coats and clarks thread but it just just says

    all purpose thread im sewing a block quilt out

    of cotton squares but dont know what thread to

    use. thank you

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