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How To Read A Knitting Pattern: Substituting Yarn Fiber and Weight

Blog » Reading Knitting Patterns » How To Read A Knitting Pattern: Substituting Yarn Fiber and Weight

How To Read A Knitting Pattern: Substituting Yarn Fiber and Weight

Liat Gat - Founder

December 14, 2010

Don't let not having the exact yarn called for in a pattern stop you from knitting that pattern! Here's how to understand the yarn requirements of a pattern, and make substitutions in yarn brands, weight, and fiber.

To continue our discussion from last week’s post on How To Read a Knitting Pattern – Size, Measurements, and Ease, let’s talk about yarn!

It’s the key ingredient in your recipe – make sure you choose it carefully.

Your pattern may suggest a yarn choice for you, but let’s delve deeper into why it is suggested, and how a little extra knowledge can make a big difference.

Malabrigo Chunky - Polar MornChoosing Yarn: What Kind, How Thick, and How Much

Designers will give you the thickness and yardage of the yarn you need to use to make the garment.

They’ll also tell you the exact yarn they used in the pattern photograph.

WARNING: The exact yarn used in the pattern is not always the best yarn to make your project out of.

Why? A few reasons. First, yarn companies often provide yarn for free to designers publishing projects in magazines, thereby limiting the designers’ choices.

Louisa Harding Ribbon YarnAlso, the magazine itself will often dictate the exact yarn that must be used. This means the designer often does not have a choice about the yarn used.

Instead, they will probably make they garment for themselves later in their favorite yarn – one that may be prettier, softer, and even more suited to the pattern.

More suited to the pattern?

What do you mean? Okay – here is your crash course in selecting yarns.

My complete knitting course, “Become a Knitting Superstar!” contains a full description of how to chose the right yarn for your project, and teaches you about substituting yarn if you need to do so.

But basically: choose your yarn according to the desired look and function of the finished project.

Gossamer CollarFor example, some garments are meant to have structure (eg. socks).

Some are meant to be ethereal and light (eg. lace shawls).

Some projects look best with a shiny, bright yarn (think silk gloves).

Some look best in a rugged tweed (like a peacoat).

Some should be able to be washed repeatedly (like dishcloths).

If you use the wrong kind of yarn (and by that I mean the wrong fiber content or blend) your socks will come out saggy, your dishcloths will shrink, and your arm warmers will be itchy.
Cheat Sheet for Choosing Yarns

Pick The Right Thickness: Understanding Yarn Weight

The thickness of the yarn you choose is called its weight, and will be specified in the pattern. From thinnest to thickest, yarn weights are called:

Yarn Weights and Thicknesses

  • Lace
  • Fingering/Sock
  • Sport
  • DK
  • Worsted
  • Aran
  • Bulky
  • Super-Bulky


Make Sure You Buy Enough Yarn: Understanding Yardage

Lastly, the designer will specify how much yarn you need for each size.

Again using parentheses, it will look like this: 1895(2045, 2200) yards.

For large projects, I recommend buying an extra ball or skein of yarn. You can always return it if you don’t use it. Running out of yarn really sucks.

If you liked this article on understanding and substituting yarns, let me know by leaving a comment!

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18 thoughts on “How To Read A Knitting Pattern: Substituting Yarn Fiber and Weight”

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  1. This is so helpful to all knitters, but especially to those just starting out on their yarn journey. Did you know there is a mathematical formula for substituting both yarn and needles in a pattern? I’ve used this successfully for years and have never had a problem (and I’m NOT a math genius)—-of course considering the appropriateness of the substituted yarn. The person who sent it to me didn’t know it’s exact source:
    I have this formula for converting any pattern’s yarn and needles to any other yarn. I got it from a very early Knitter’s magazine. Say that you’re getting 6 stitches to the inch, and your pattern says 3 stitches to the inch. (Doesn’t matter if you’re using the same size needles as in the pattern, the same size yarn, or anything.) Divide your gauge, 6, by their gauge, 3, and you get 2.* That’s your “conversion factor.” Now multiply every number in the pattern by 2, and you’re set. Works really well for me, cos I knit loosely.
    *Doesn’t matter if your number is larger or smaller than their number.

    My own note is that if you get a decimal, i.e. 8.6, use that total in your conversion—-if you come up with any number over .5, round up to the next whole number, or down if it’s less than .5. If you are using a stitch pattern, you can’t alter the numbers in the stitches, you need to make repeats fit into the total stitch count. You apply this formula to every number in your pattern. Rows may be a different formula but I don’t usually worry about that since most row counts are determined by a measurement anyway.
    Norma Byrd

    1. Hi Norma,
      This information is amazing. I wish I had tried it out recently on a hat I knitted where my gauge was much tighter than the suggested yarn. I kept on re-casting-on and trying the hat on, but I still made it too big. I actually may just knit another hat, using my first hat as a gauge swatch, and make the calculations you suggest, as a way of practicing this technique so that I can really understand it. I had not heard of this before and it is genius.

      Thank you so much,

  2. I liked your article on substituting yarn.
    Have you written a book? I enjoyed your article describing your history with knitting and your eating disorder!
    Consider writing one if you have not. Take care!

    1. Hi Kathleen,

      Thank you so much! I have written a knitting book in 2014 called the Fearless Knitter, but my publisher kept on firing my editors and so it never went anywhere. I may put the whole thing up on my website someday just so it’s out there.

      Thank you for the encouragement! I really appreciate it.


  3. Thanks for choosing this topic to describe. I always need to be reminded of the weights and the value of different yarns.
    Also, didn’t know or think about why designers use a certain yarn. Gives me more courage to branch out.

  4. Kia ora Liat, great info thanks! One thought: many countries use international sizing – mm for needles, and ‘ply’ for yarn. Including the same chart with these would be so helpful.

    Cheers, Kuini

  5. Recently I’ve been using a Japanese yarn that I’m in love with and sometimes there is no standardized labeling of the yarn size. I have a story of a yarn store and my sister that explains why this is relevant. Anne (my baby sister) wanted me to knit a pattern she found in a magazine for her daughter my niece. She bought the magazine in store but the named yarn wasn’t available. The yarn store guru helped her pick a substitute yarn and had it mailed to me. Wrong size and I had to return and go to my LYS to order the correct yarn.

    1. Skye Jameson - Knitting Expert

      Hi Steven,
      Thanks for sharing! I am curious about the Japanese yarn? What are you knitting with it, and how did you determine its size? I bet it is beautiful.

  6. Saw a pic of really bulky bedspread. I don’t know where to get that and what size needles. It’s for a double bed

  7. I have been knitting and crocheting for many years. Made my first sweater at age 10.
    I am now 74 years young. I am a caregiver for my DH, and am so happy to have this site to learn new things. We never stop learning.
    Liat, you are a wonderful teacher, and I feel honored to have your expertise right in my home. Thank you for all you do. Judy

  8. I would have been THRILLED to have found an article like this in my early days of knitting (not that I didn’t still find this helpful!). I was so clueless back then, and I didn’t have an LYS. I love your non-confusing way of teaching (sharing your knowledge)! :-)

  9. I love your site, I am a lacemaker, needle, and recently had eye problems and could not work my lace. I returned, after many years, to knitting, wow what a change and what an exciting new world I have discovered. Thankyou Liat for sharing all your wonderful information and technique. Tricia Girolami, Italy.

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