Mystery Yarn? How To Determine Yarn Weight

Mystery Yarn? How To Determine Yarn Weight

Mystery Yarn? How To Determine Yarn Weight With WPI

Have you ever been given yarn with no label or lost the label to yarn you bought? I have! Trying to decide what the weight is can be extremely frustrating!

Not anymore! Using a little trick called WPI (wraps per inch) you will be on your way to happily crocheting!

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How does this work?

Yarn weight is calculated by the diameter of the strand. So a bulky yarns work up more quickly because of the thickness of the strand and on the flip side lace weight yarns more slowly because of how thin they are.

Wrapping the yarn around a pencil (or any uniform object with consistent circumference, like a dowel, knitting needle, etc.) determines yarn weight because bulky yarns take less wraps than light weight yarns. The diameter of the object you wrap around is not important as we are measuring the yarn strands thickness not the length. Think of the strands as side by side.

To figure out yarn this mystery yarn you will need:

  • Mystery Yarn
  • Measuring tape
  • Round uniform object (pencil)

Begin by wrapping the yarn around your pencil, not to tightly and make sure the strands do not over lap or leave spaces. You want them to lay next to each other  comfortably.

Now count the number of times you wrapped the yarn in the length of an inch.

Next compare your numbers with the WIP chart below~


0 – Lace weight yarn >35 >8.5 sts/inch
1 – Fingering weight yarn 19-22 7-8 sts/inch
2 – Sport weight yarn 15-18 5.75-6.5 sts/inch
3 – DK weight yarn 12-14 5.5-6 sts/inch
4 – Worsted weight yarn 9-11 4-5 sts/inch
5 – Bulky weight yarn 7-8 3-3.75 sts/inch
6 – Super-bulky weight yarn <6 1.5-3 sts/inch


My mystery yarn is a fingering weight. It wrapped around my pencil 20 times.

You can also buy a little WPI tool that measures and holds the yarn in place while you wrap. I have not gotten a chance to use one, but if you spin your own yarn or find yarn without labels a lot getting one might be useful.

Quick Tip!

If you are wrapping yarn with an inconsistent strand like homespun yarn you can wrap around 2 inches then say you have 18 wraps divide this by the 2 ( from inches) to get your WIP. So 18 divided by 2=9. So on the chart my homespun yarn would be a 4 worsted weight.

Ready to find out what that Mystery yarn could be??

I hope you find this post helpful! I know WPI really helped with me.

Have a lovely crochet day,



This Post Has 2 Comments

  1. You are the best. Thank you for sharing that.

    1. I’m really happy you liked this post! Thank you for the visit and leaving a comment!

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