How to calculate yarn length from weight

We’ve all been there. We’ve got a big pile of yarn (inherited from a family member, the result of frogging a project, or maybe even a thrift store find)… and we have no idea how much yardage there is!

Since most patterns specify the number of yards you’ll need, determining the yardage of your yarn is crucial. Fortunately, it’s not too tricky! In this post, I’ll show you how to use a scale to calculate the yardage of your yarn.

Materials required


To calculate the yardage of your yarn, you’ll need:

  • the yarn (duh!)
  • a digital scale
  • a box or bowl (to hold the yarn on the scale if you’ve got a lot of little bits of yarn)

Step-by-step: How to determine yardage

Got your materials together? Okay, let’s get started!

Find out the yarn’s yardage per weight information

I lucked out a little bit: I had a big bundle of yarn that came along with a label. The label tells you how much length/weight a particular ball of yarn is:

If you aren’t lucky enough to have a label, you have some options:

  • If you know the type of yarn you have, look it up in Ravelry’s yarn database. It’ll tell you the yardage/weight.
  • If it’s mystery yarn, you’ll have to manually measure and weigh a small sample. Boring, but easier than measuring the entire amount of yarn!

Calculate length per unit of weight

Now I know that my yarn has 100 meters in 50 grams. I want to calculate how much length there is to each gram.

So, each gram of yarn is 2 meters long. We’ll keep this in mind!

Weigh your yarn

Since I have a lot of little balls of yarn (the result of frogging a sweater), I’m using a box to keep them all together on the scale. Put the box on the scale, and zero the scale:

It’s important to put the box on the scale before you zero the scale, so that the box won’t be included in the weight. Zeroing the scale just means that you’re telling the scale to start at zero… and it’s easy to do. On my scale, I just hold down the ‘tare’ button. See how it’s now reading ‘0’?

Since my yarn label listed the length/weight in metric, I’m going to weigh my yarn in grams.

Put the yarn that you want to weigh in the box:

And weigh it!

And it weighs…

472 grams. Good to know!

Calculate the yardage

Now all we need to do is calculate our yardage! We know (from before) that each gram is 2 meters long, so we multiply 472 (how many grams we have) by 2 to get our total meters.

To do the final conversion from meters to yards… you don’t even need to do any calculations! Just type ‘convert 944 meters to yards’ into Google, and it’ll give you the answer!

What will you make now?

Now that you can determine the length of some of your mystery yarn, what are you going to do with it? I turned mine into a Kyuu cardigan… I’ll update you on that, later!

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