Calculating Yarn Weight

December 29, 2020

2 minute read

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A question that I see crop up fairly often is how to calculate the combined weight of two strands of yarn held together. Or, sometimes, a knitter wants to achieve a certain weight and wants to know what weight(s) of yarn to hold double.

There are a few ways to work this out, but there’s one method that I like more than others, and that’s by calculating the combined meterage (or yardage – units don’t matter as long as you’re consistent) per 100g, and then seeing what weight yarn that is.

I need to give credit where it’s due: I learned this method and how to calculate it from a spectacularly helpful blog post by Susanna Winter of Talvi Knits. I’ve got no additional wisdom to add to her wonderful explanation, so please go read her post about how this method works by following this link.

What I have to offer here is code. If you don’t want to do the maths yourself, you can stick your numbers in the calculator below and it’ll tell you what weight yarn they make when held together. Nifty, huh?

How to Use

It’s pretty simple! To find out what weight two yarns held together will be, all you need to do is find out the meterage or yardage for each yarn (be consistent!) and then:

Enter the meterage (or yardage) per 100g for the thinner yarn in the top box. This will be the bigger number.
Enter the meterage (or yardage) per 100g for the thicker yarn in the bottom box. This will be the smaller number.
Check the third box to find out the combined meterage (or yardage) per 100g.
Look up this value in the table below to find out what yarn weight this is equivalent to.

If you know what combined weight you’re aiming for and the weight of one yarn but not the other, it’s a bit trickier to work out. The best bet is to use trial and error. Remember to switch around which number is in which box if need be!