How To Substitute Yarn In A Knitting Pattern


In this post, we will look at how to substitute yarn in a knitting pattern.

Substituting yarn in any knitting pattern will help you to transition from beginner to more advanced and will allow you to be more creative with your knitting.

This will give you the ability to experiment with a variety of different yarn colors and finishes.

Learning the skill of yarn substitution will provide you with the freedom to explore a range of different fibers other than those recommended in each knitting pattern.

yarn filled shelves for how to substitute yarn in a knitting pattern

Why Would You Choose To Substitute The Yarn?

Let’s say you have way too much yarn of a specific type of yarn in your stash, but it’s not the yarn recommended and used in the pattern, wouldn’t it be great to use the yarn you have at home?

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Also, let’s say you are allergic to a certain fiber, for example, alpaca fibers.

Does that mean you can’t make certain patterns using this yarn? No…

It means you are going to learn to substitute this yarn with one that you can use/like. 

Yarn in a bag

Yarn Substitution Made Easy…

Yarn substitution can be a scary idea for anyone less experienced with reading knitting patterns; however, it’s easier than it seems!

Once you’ve mastered how to substitute yarn in a knitting pattern, you will be well on your way to creating a wide range of items in different colors and finishes.

To work out what you can use instead of the yarn suggested by your pattern, simply follow these three simple checks outlined below.

How to substitute yarn in a knitting pattern

1. Check The Gauge And Weight

The first step in yarn substitution, and to ensure you have the correct weight or thickness of yarn, is to check the pattern’s size gauge.

From here, you can establish exactly how many stitches and rows per inch your substituted yarn will need to match.

If your new thread is a good substitute, it should knit to the same size.

yarn basket for substituting yarn

The gauge is important

Your gauge will usually say something like “8 sts and 17 rows, to 10 x 10 cm using size 9mm knitting needles”; which would tell you that your yarn should measure 10 centimeters by 10 centimeters, for every 8 stitches and 17 rows that you knit (using 9mm needles).

Whichever option you decide to substitute your original yarn for, make sure it matches your gauge – if it doesn’t, your finished item could end up a very different size.

In addition to using the knitting pattern’s gauge, the yarn specified in your instructions should also give you an indication of the ideal weight and thickness required.

Most designs that supply details for the gauge will also give you the weight.

yarn label

Image Source – Lion Brand Yarns

Yarn weights

Yarn weight will be listed under a variety of different types, for example:

  • DK weight yarn
  • Aran weight yarn
  • Chunky yarn
  • Super bulky yarn
  • Worsted weight yarn
  • Fingering weight yarn
  • Sport weight yarn
colourful yarn collection

Know your yarn weights

Knowing the weight of the yarn that you require will help to narrow down your search, and will make shopping for your substitute yarn much easier.

If you’d like to know more about the various types of yarn weights, read my guide – Yarn Weight Guide (+ A Conversion Chart).

You can also check out this handy yarn weight chart below for you to pin for future reference.

Yarn weights and categories

2. Check The Fibre

As each ball of yarn will behave very differently from the next, it’s essential to find out the composition of the original yarn.

For example, a woolen hat that you would want to wear for insulation in winter won’t do the same job if made from lighter-weight cotton yarn.

Acrylic fibers can also feel very different from natural wool, so it’s always best to check the exact material composition before you buy.

The fiber content is key, you can’t expect a 100% wool yarn to produce the same elasticity and fabric as an acrylic blend yarn.

Related Post – Yarn Types Explained: A Guide To Different Fibers

yarn and knitting needles

Choosing the fiber type

The best rule for yarn substitution is to select a type of fiber that resembles the original thread as best as possible.

Your pattern will be designed for a specific kind of weight and finish, so it’s usually best to try to stick with the same fiber specified (or as close to it) so that your finished item looks as you expect it to.

yarn with acrylic fibres

3. Check The Length

A knitting pattern will always state how many balls or skeins of yarn it will require; however, this will usually change when substituting yarn for a different type.

Not all yarn balls are created equal, and they often have very different lengths.

If you can’t find the yardage on the pattern page it’s always available on the shop page of the yarn if you are shopping online or on the yarn label if you are visiting your yarn store. 

To work out the total length you will need of your substitute yarn, use this simple two-step calculation to establish the length and how many balls you will need:

how to read a yarn label

Image Source – Lion Brand Yarns

Calculate the original total length

  • Take the number of skeins required for the pattern and then find the length of one of those balls of yarn.
  • For example, your knitting instructions state 8 balls of yarn, with one ball measuring 100 metres.
  • Next, multiply that individual length by the total number of balls required: 8 x 100 = 800 metres.
yarn shelves filled with cotton

 Calculate the quantity of substitute yarn required to complete the pattern

  • Find out the length of one of the new balls of yarn.
  • For this example, let’s say our new thread is 95 metres.
  • Then, divide the total yardage by the length of one of the new balls of yarn: 800 / 95 = 8.4.
  • This calculation gives us 8.4. balls or 9 once rounded up.
knitting needles and yarn

Final Tips and Advice

So, we now know that to complete this pattern with our substituted yarn, we will need nine balls.

Now that you’ve learned how to substitute yarn in a knitting pattern, you will find that you can create more items in a much wider choice of fibers and finishes.

Next time you head to your local knitting shop or you’re shopping for knitting yarn online, why not try yarn substitution and see what you can make!

Here are some tips to remember:

Tip 1

  • If you don’t want to use or can’t find the specified yarn on a knitting pattern, you could go to your local yarn store and ask for some help from the people who work there.
  • Chances are that anyone working there will be an experienced knitter and can give you some good advice.
  • You could also join some knitting groups on Facebook and ask in there for some help.

Tip 2

  • Just because two yarns have the same gauge doesn’t mean that they can substitute for each other successfully in a given pattern.
  • If they have different characteristics – texture, drape, fiber and colour, then the final garment will look and feel different from the one pictured on your pattern.

Tip 3

  • Use a tool – like this one from YarnSub.
  • There are tools online that can help you to find a yarn for your project
  • If you have a yarn listed on a pattern that has been discontinued, just type it into the search box and the tool will help you to find a substitute.

Tip 4

  • Swatches are your best friend.
  • Let’s say you did all the math and you found the right yarn sub for your sweater.
  • Before starting your project it’s always better to make a small sample using the patterns stitch pattern, to make sure everything is going as planned.
  • Remember never two strands of yarn are made the same.
  • Swatches are also a great way to check the stitch definition. 

Tip 5 

  • Ravelry can be a great source of information.
  • Ravelry is not only full of patterns but also has a great yarn information library.
  • And there you can find information about the weight category a yarn belongs to, its fiber content, etc. 

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  1. Hi Louise,
    Thank you!
    My question – how to substitute a different type of yarn unlike suggested pattern yarn to fit.?

    1. Hello Linda, you need to make sure you select a yarn that is in the same weight/category as the yarn given in the pattern.
      For example, if the pattern gives you a bulky yarn weight to use, you would also have to substitute it with a bulky weight yarn.
      If you use a different weight, then the end results will be different.
      Sometimes you can make the weight you need by knitting with two strands together, so if you wanted a bulky weight and knit with two strands of worsted or Aran together, that would also be ok to do.
      But you would need more yarn obviously.
      If the pattern does not give you the yarn weight, google the yarn it suggests to find that info or by the needle size given.
      I hope that helps!

  2. Do you have the web site of GOOD YARN STORES that have a WIDE VARIETY of good yarns? I would appreciate any you could supply..

    1. Hello Susan,
      You could try the Love Crafts website, they have quite a variety of yarns.
      It depends on your location…in the US you could also look at the Lion Brand website.
      In the UK Wool Warehouse is also good.
      I also really like the yarns from We Are Knitters.
      I hope that helps,

  3. This is an EXCELLENT ARTICLE. I needed this today because I am trying to substitute a particular Aran weight yarn. Thank you so very much for these pointers..

  4. My issue is that I have a LOT of yarn that was donated to my Needle Arts Club while I was still teaching. The good stuff came home with me when I retired (the club was folding, sadly) and some of it is without their labels. How do I determine what the weight of mystery yarn? I’ve read something about winding around a pencil and measuring the number of winds in a certain space. Is that a good way? Can you elaborate? THANKS for your site; I’ve already pinned a lot of good information :).

    1. Hello Elaine,

      Determining the weight of a mystery yarn can be a bit challenging without the yarn label or any specific information. However, you can use a few methods to get an approximate idea:

      Visual Comparison: Compare the mystery yarn to known yarn weights. Hold it up against different yarns you have that are labeled with their weights (lace, fingering, sport, DK, worsted, bulky, etc.). See which weight category it closely resembles in terms of thickness.

      Wraps per Inch: This method involves wrapping the mystery yarn around a ruler for an inch and counting the number of wraps. Then, compare this number to standard yarn weight wraps per inch. For instance, lace weight might have 18 or more wraps per inch, while bulky yarn might have 7 or fewer wraps per inch.

      Yarn Weight Chart: Use a yarn weight chart as a reference to match the thickness of the mystery yarn. There are many online charts available that provide information on yarn weights and their corresponding wraps per inch, recommended needle sizes, and gauge.

      Gauge Swatch: Knit a small swatch using different needle sizes to determine the fabric density and thickness. Compare the resulting fabric to known yarn weights to see which weight it most closely resembles.

      I hope that helps!