There are two widely used methods for measuring spun yarn. One, the yards per pound measurement, is usually taken using a piece of equipment called a McMorran Balance. There’s a good article in the Summer 08 Spin-Off explaining this. A McMorran measurement, however, won’t really tell you how thick your yarn is - a heavy, drapey fingering weight may come up at the same ypp (yards per pound) as a light poofy DK, as the yarns each have the same amount of fibres, just spun in a very different way. Measuring the wraps per inch (wpi) will tell you the exact grist (thickness) of your yarn, although it won’t describe the density for you. Combining both measurements will give you the most complete picture.

Firstly, why would we even measure wraps per inch? Well, a few reasons. Taking notes of measurments such as grist, ratios spun and so on, gives you valuable information should you want to recreate the yarn at a later date. It may be that you want someone else to be able to recreate the yarn - e.g. in a published pattern. The more information you have, the better.

Measuring the wpi is also a good way to check a substitute yarn. Commercial yarns give a gauge on the ball band, but rather than knit swatches with all your handspun to find a match, you can simply measure the wpi of the commercial yarn, and those of your handspun skeins. Knowing the wpi can also give you a starting point for needle size - there’s a handy table in this article listing wpi and equivalent gauge.

So how is it done? Measuring wpi is quite simple really, however there are variables in play and it’s a good idea to practice a bit to make sure you are consistent. Instructions such as ‘wrap evenly and not too tightly’ are actually quite subjective, you may wrap ‘not too tightly’ with different judgement to someone else. If you know that you are always consistent yourself, then that is a good starting point.

Specially made wpi tools like this one are handy, but not essential. You can wrap your yarn around anything with measurements marked on it - or even a piece of dowel with tape markers. Wrap slowly and evenly, placing each layer next to the last without squashing them. This is much easier with smooth, drapey yarn than soft and puffy!


Continue until your inch is full - don’t be tempted to stop at half an inch as your reading may be inaccurate. Check that the yarn is not too tight or too loose, the threads should be touching, but not squashed. This yarn measures 12 wpi.


And that’s all there is to it! Practice measuring your yarn - find some commercial yarn you think looks the same as your handspun then measure them both to see how close you were. Measure different parts of your skein to check whether it’s even. Measure everything in sight until someone gets tired of you and takes away your ruler :-)


I have two little wpi tools to give away this week - leave me a comment telling me what you’re spinning today and on Thursday morning I’ll draw some names out of the proverbial hat. Good luck!

Don’t forget, we’re now on Lingr. Pop by today for a chat :-)


31 Responses to “Spin-In: Measuring wraps per inch”
  1. Fiona says:

    This is very timely - I’ve got some moorit Shetland on the wheel right now, which I hope is going to end up as something approximating worsted weight. And it’s not easy for a beginner like me!

  2. Caro says:

    Well, yes, I need me one of those. I measured my first spindle-spun 50g BFL skein at 15wpi. It’s at least aran weight. Hmm.

    And spinning today? Some Gotland from Spindlefrog on etsy. It’s lovely, silky, steel-grey stuff, and I’m totally messing it up. At first, I was dropping the spindle literally once a minute, as the long fibres drifted away from each other. Now, I’m putting much more twist in, but struggling a bit to keep it out of the drafting triangle, when everything freezes up. A slow business, but fun.

  3. Carie says:

    Thanks for the tutorial - I’m spinning a second ‘bobbin’ (aka straw) or BFL in wonderful orange/purple/pink/red/brown colour which will eventually become my first pair of handspun socks.

  4. Jagienka says:

    I’m in the middle of spinning lovely merino/ tencel blend in a spring green/ soft pink colour. I was aiming for laceweight singles but I think I’m spinning cobweb! Will have to ply it before I knit anything with it. Right now I think I’m getting >50wpi…

  5. Chris says:

    That is the best explanation I think I’ve read of WPI - thanks. I’m trying to finish up some really pretty Autumn colored BFL I started spinning on Vacation…..

  6. Jen says:

    Thanks, I’m ripping up silk hankies and admiring Amy now that I’ve blocked it.

  7. SylvChezPlum says:

    Thanks for the tute, I’ve tried measuring the wpi before but couldn’t quite figure how much “squashed” is too much.. I’ll try it again soon.
    Spinning some wonderful textured batts today, love the result ! :-P

  8. Brightsider says:

    Thanks for the photo of the WPI tool- I always wonder if I’m squidging it up or stretching it too much.

    Today I’ve been plying the next batch of merino/silk for the shawl. I’m doing this one in smaller chunks so that I don’t have to spend a whole week just plying this time! I’ve already started the next spindle full on the Golding.


  9. Kate says:

    I don’t count as a spinner, but just wanted to say that those tools are really cute. :-)

  10. Julie says:

    I admit to usually just eyeballing my yarn rather than using a wpi tool as I should. Today I am spinning a silk/angora/wool blend that I’ve just attempted to blend on my newly acquired budget hackle and diz. (Being totally inept at the hand combs I hope the hackle would be easier and so far that seems to be true.)

  11. JC says:

    I’m spinning some beautiful natural alpaca- my first! It’s coming along beautifully, and I’m so pleased!

  12. Sara says:

    great tutorial! right now i am spinning 4 oz of crown mountain farms superwash merino in under the boardwalk as a 3ply sock yarn.

  13. DebbieB says:

    I have one of those wpi tools - Sherie gave it to me in the Spunky Swa(m)p. I love it! Mine has a kitty with balls of yarn.

    I’m plying today - some laceweight merino/possum singles I spun this week - on my new Suzie Alpaca.

  14. Moggle says:

    I’m spinning some bfl/tencel and trying to get proper sock weight/thickness.

  15. Sally says:

    I’m spinning some Yarn Yard BFL in beautiful bright reds, yellows and oranges. Somehow the colours feel a bit autumnal even though they are so vivid and not at all subdued. I needed some brights to cheer me up because it’s so bleak outside!

  16. Tina says:

    On one wheel, I spin flax. On the other, I just finished plying a sample skein of combed wool from an indigenous Swedish sheep. I haven’t decided on a new project for that wheel yet, but I’ll probably spin some dyed merino/silk.

  17. Barb Fessler says:

    Wonderful little gadget!!!
    I’m carding white merino and gray mohair together then spinning and plying it. I like the softness of the merino and the shine of the mohair.

  18. Donyale says:

    I reached for mine (albeit without VERY cool logo of yours) and wrapped away. Good to know. Thanks

  19. Amanda Cathleen says:

    thanks for the great post Diane, a spinning friend and I where just chatting about wpi last week.
    ummm… the wheel is still packed up in its little bag from my trip 3 weeks ago. there has been so much stuff to finish i haven’t been able to find the time to unpack it. I was spinning one of the batts I picked up at SOAR.
    ya know what, I’m going to unpack it tomorrow. Its time to spin.

  20. Elly says:

    I’ve just finished spinning some merino on the wheel (pic on my blog). My first wpi was 7, I tried again and got 10. Need to work on that! That and winding yarn on a niddy-noddy. Any tips for that would be gratefully received!!

  21. Jo says:

    I’m spinning some merino….it’s a new batch from a new supplier, quite a different feel to my usual supplier so I had to try some out, the colours are deep aubergine, with purple, pink, ginger, and I was hoping for a worsted weight, checked the wpi and it’s 11!

  22. Lydia says:

    Thanks for pointing out that the way to go about this is to get to learn my own wrapping style. This week I thought I would take some time and use samples of different kinds of wool that I have (Jacob, Shetland, Massam, Welsh) as I am more and more intrigued by natural colours and am dreaming of having a sweaters worth of hand spun one day.

  23. Janelle says:

    I’m a pretty new spinner and right now I’m spinning some wool from a sheep named Heidi. The fiber is called “Heidi’s Blues” because of dye. I’m not even sure what breed of sheep it is. Looks like this:

  24. Mary-Kay says:

    Wow, I just discovered your blog and site and have bookmarked it to no end. Excellent. Right now I’m spinning a very cool batt made of silk, bamboo, angelina, and merino, about 5.6 oz. The colors are greens, blues, and white. It’s taking quite a long time but I LOVE it. I’m hoping to have the second bobbin done today and I’m planning on plying it into laceweight. I’m thinking I might make a shawl out of the end result, but I need to know what the yardage will be. You can see my other spinning I’ve done lately on my blog…. I just took Lexi Boeger’s class to learn how to spin the crazy batts, and that was a BLAST!

    Thanks for all of your cool information - I’ve seen this tool, but I’ve never used one.
    If I don’t win one of these cool tools, can you tell me where to buy one? I think I need one for sure!


  25. Beverly says:

    Another new reader here - have been dipping into your older posts, lots of info there, thanks!
    I have a “clump” of alpaca that went through the dyepot in a nylon stocking (guild dye-day) and is no longer roving. I tried fluffing it with my hands and spinning from the “cloud”, with limited success….not my usual smooth handspun for sure. But a nice change for the spindle and I’ll find something to do with a little skeinlet of lumpy yarn…

  26. Emilie says:

    Oooh, pretty. :) Ok, I’ll bite.

    Today I’m spinning some rainbow dyed BFL fibre that I got from the Wool Clip. I’m terrible at knowing whether I’m spinning worsted or woollen but I’m spinning carded fibre and I think I’m doing what you fancy folk would call a short draw. My singles aren’t airy or squishy but the plied yarn is. I’m spinning 50g to combine with another project and I’m spinning a fingering weight yarn.

    :) Thanks for your tips on WPI!

  27. Mary L. says:

    I am spinning, or just finished spinning some merino roving in dark green with some reds that I won in a contest over at Craft Leftover. I’m glad this post is about WPI, but I was wondering… I have seen wpi charts that have vastly different number for how many wpi a particular weight yarn should have. I mean, compare the chart on the knittyspin article you mentioned with this chart that the girl from auntie uses. I’d like to understand.

  28. Mary L. says:

    oops, and here’s the chart at the girl from auntie.

  29. Traci M. says:

    I am spinning the last of a beautiful white correidale fleece. With what was left, I broke it apart into equal amounts and dyed it in all different bright colors, then carded it together for christmas socks. My son’s girlfriends have all requested home made socks for christmas. 2 pair knitted….2 pair to spin and knit.

  30. mrspao says:

    I’m going to spinning up some of the white fleece I got from a farmer last year. I think the WPI tool is fab.

  31. Going Listed here says:

    Going Listed here…

    Needles on the Move » Spin-In: Measuring wraps per inch…