What yarn should I use? How to substitute yarn in crochet patterns

You’ve found your perfect pattern, your hook is at the ready, but you don’t have access to the yarn that’s called for…

Fear not, this post will help you decide what factors to consider when choosing what yarn to use as a suitable substitute for your crochet project.

I want to start by saying that it’s important to remember that crochet, and yarn craft is an art, not an exact science (despite the importance of and reliance on the maths). There are no absolute right or wrong answers.

I talk about this a lot in various posts, but we all crochet slightly differently, so it’s hard, if not impossible to exactly reproduce items we may see in a pattern.

However, understanding what factors go into making your crochet project, such as yarn selection, will help you make a choice that works for you. Learning the fundamentals of yarn selection will really help improve your crochet success rate.

The advice given below talks largely about substituting yarn in crochet patterns but the same principles apply if you’re freestyling your crochet project and don’t know where to start.

When substituting for a different yarn to that given in a crochet pattern, there are 3 essential questions to consider:

• Is it the same yarn weight?
• Is the fibre content (and how it’s spun) the same?
• Does it match gauge?

The answer doesn’t always need to be yes to all of these questions, but understanding how the no’s will impact your crochet project will help you make an informed choice.

I will discuss each of these features below but before I start, I to give an overview as to why the type of yarn you use matters in the first place.

Why does it matter what yarn I use for a substitute?

When a crochet pattern is designed, it is done so (usually) with a specific yarn in mind. If you use a different yarn then you are going to get a different result.

Let’s say you’re working a hat pattern designed with double knit cotton and you substitute it with a chunky merino yarn, your finished hat is going to be a very different size and structure from the one in the pattern.

That’s an extreme case, but it illustrates the point that the type of yarn you choose will alter the finished look and function of your project. That’s not to say you can’t substitute cotton for merino, you absolutely can, but you need to know how this is going to impact the project as a whole.

If you’re starting from scratch then the yarn you choose for your crochet project depends entirely on what type of project you’re going to crochet, what it needs to do and what finished look you want to achieve.

Here’s my number one yarn sub tip to swear by;

You should (almost) always swatch anyway, but in the case of yarn substitution it is important to understand how your chosen yarn will behave in the context of your crochet project.

Swatching will help you make your own choice as to whether that is suitable for your preferences.

It’s common to get yarn substitution a bit wrong when you’re learning about different yarns. I know I made some pretty interesting substitutions when I started crocheting, but it helped me learn. And I am still learning, so any suggestions here, are just my personal experience.

My second top tip for yarn substitution;

Check out yarnsub.com which has great information and suggestions on specific substitutions.

Okay, with the brief ‘why’ out of the way, lets look at the properties of yarn you need to consider when substituting.

Why yarn weight matters for substitutions

A yarn weight fail

When I started crocheting and hadn’t even heart the term ‘yarn weight’ let alone understood it, I remember trying to make a hat using double knit (dk) yarn from a pattern which called for worsted. (In the UK it seems that DK is used more commonly whereas Worsted Weight seems more popular in the US).

My hat came out way too small and I had no idea why. (I didn’t understand gauge either)

Ultimately, it was a helpful mistake because it got me interested in different types of yarn and set me on this path of discovery and experimentation.

Yarn weight is, in my opinion, a bit of a misleading term. It’s not about the weight the yarn in grams or ounces, it’s a term relating to thickness of the yarn.

On a basic level, the ‘heavier’ the yarn, the thicker the strand.

If you are new to the term yarn weight and want to understand it in more detail, then you may want to start with this post which explains what yarn weight is and what all the terms mean.

So why is yarn weight important?

Well that that dk yarn I used for the hat I mentioned was a lot thinner than the worsted weight suggested. So I needed to make a lot more stitches with that thin yarn to achieve something the same size made with the thicker worsted weight.

If you’re familiar with the concept of gauge, then this will make sense.

When crochet designers write their patterns, they do so using a specific yarn which helps them achieve a specific gauge. All their stitch counts and calculations are based on that gauge.

Tip 3 for substituting yarn;

When you are choosing yarn for your project, start by looking for something in the same weight category.

I say start by looking in the same weight category. The yarn weight is usually given on the yarn label along with the fibre content.

However, there can be a lot of variation within a single category (due to factors like fibre, twist and ply), which is why yarn weight is only a single piece of the puzzle.

To add more complexity to the situation, there are many ways of categorising yarn weights which differ between countries and yarn brands.

You may want to have a look at this page which lists the most common yarn weight terms used (including conversions for different countries), along with offering a suggestion of what hook size to use with what weight.

Yarn substitution and fibre content

When I talk about fibre content, I’m talking about what the yarn is made from and also how it is spun.

Yarn can be made from cotton, acrylic, wool, alpaca, silk, cashmere, mohair, bamboo, linen, nylon, cashmere, angora, or a blend these and or other various fibres, with new fibres such as nettle and corn (yes, corn!) coming on the market all the time.

Different fibres have different properties, that is, they behave in different ways. If you take a pattern designed for a cotton yarn and work it with mohair, it’s going to look very different.

That’s not to say it won’t work or it’s wrong… It may look epic, but it’s important to know that the fibre you choose will effect the finished look and feel of a project, so it’s something you need to bear in mind.

Switching cotton for bamboo usually works pretty well as they are both plant based fibres with similar properties. For example, an amigurumi written using cotton would also work in bamboo which has many similar features..

With time and experience, you will begin to learn how different fibres and types of yarn behave, noting that because the same fibre can work differently in different yarn types.

Some fibres have different levels of stretch, some can be thrown in the washer and dryer, some need hand washing, some hold their shape, some need blocking, some split easily and some are almost indestructible!

A worked example of how to substitute yarn (video tutorial)

You can check out this video all about yarn substitution using a dk mohair yarn as an example. I use a whole bunch of yarn combinations and fibres so you really get to see what fun you can have with yarn substitution!

What are the properties of yarn made from different fibres?

Fiber content in yarn can create some different behaviour in the yarn itself and the finished crochet project.

Below is a very brief summary of some common properties of the most common commercially available yarns. Note that there will be some variation depending on how the yarns are manufactured, so do take this as a general rule of thumb only.

• Mercerised Cotton: Plant based, strong, partially absorbent, smooth finish, shiny with clear stitch definition, hardy, will soften with wear / use, cooling, washable (learn more about cotton yarn here)
• Non-mercerised cotton: Strong, absorbent, mat or shiny finish, clear stitch definition, usually a very small halo, inelastic, may soften and fray with time, cooling
• Bamboo: Plant based, absorbent, soft, usually has some sheen, beautiful drape, soft to wear, some stretch, cooling, washable
• Wool: From sheep – different breeds of sheep give different wools (merino, blue faced Leicester etc), absorbent, may be smooth or have a large halo depending on how it’s spun, verifying stitch definition and drape, often stretches, warm in cold weather and unexpectedly cool in warm temperatures (sweat wicking), very versatile, hand wash to avoid felting
• Acrylic: Synthetic, non-absorbent, usually smooth threads, can be shiny or mat finish with generally clear stitch definition, hardy, washable, does not take dye, non moisture wicking so not great for warm temperatures (unless you want to get sweaty!)

Yarns often blend fibres together to benefit from the different properties. So, for example, introducing wool to an acrylic yarn might make it a little more suitable for garments (I find acrylic garments can get a bit sweaty, but having a wool element helps absorb some of the moisture and make them feel more comfortable.

Another common blend is adding nylon is to wool for sock yarn to give it additional durability (along with a high twist that’s typical of traditional sock yarn).

Tip number four for yarn subbing;

If you want to crochet something similar to the item produced in the pattern then I recommend sticking with the same or similar fibre content and twist.

This may not be possible for a number of reasons, whether it’s related to allergies, cost or availability. However there is almost always something you can substitute.

The resource I mentioned at the start, Yarnsub.com, is a great reference tool for choosing a substitute yarn because it directly compares the fibre content of different yarns. It even gives you a % similarity rating.

Fibre content isn’t all you need to think about here, you also need to consider how the yarn is spun. Just because something is made from acrylic, it doesn’t automatically make it a good substitute, even if it is in the same weight category.

It could be spun in many different ways, an ‘s’ twist, a ‘z’ twist, plied with different colours. It could be worsted or woolen spun (I talk about this in my yarn weight article), or have neps or even sequins added in. There is a big difference between something like sock yarn which is tightly spun and roving yarn which is a single ply.

But ALWAYS make a gauge swatch and see!

Fibre content and the function of your crochet project

When choosing different fibres, you will also want to consider the function of the project.

Does it need to stretch, not stretch, absorb or repel water, hold it’s shape well or create lots of drape. Do you want it to trap air for warmth or lay smooth with lots of stitch definition? All of these questions are answered by learning fibre properties.

For example, if it’s being worn close to the skin you will want something soft which won’t irritate. Some people find pure wool itchy against the skin but when it is a wool blend, it may be more comfortable.

If you’re making a dishcloth you will likely want to use a cotton or bamboo because of it’s absorbent properties – if you use an acrylic, it’s just going to spread liquid around because the plastic won’t easily absorb liquid.

Which brings me to my fifth tip;

When switching yarns, try to find something which behaves way that supports the function of your crochet project

What is your yarn’s halo like?

The term halo, in the context of yarn, refers to the level of ‘fluff’ (for want of a better word!) around the core of the strand of yarn.

This is also referred to as the ‘loft’ of the yarn – a lofty yarn is one which kind of takes up space because of the way the fibres are spun.

Yarns with larger halos will generally have less stitch defection.

Something like mercerised cotton has almost no halo, wool typically has at least a small halo (depending on how it’s spun) where as mohair or suri alpaca has a much bigger one.

The size of the halo should be considered when substituting yarn, especially when it makes a contribution to the yarn weight.

Check the halo in the original yarn and try and work with something similar to achieve the same look.

When swatching, make sure you use the same stitch pattern you’ll be working with to get a proper comparison.

An aran weight mohair may look much finer than an aran acrylic yarn, but if you want the halo to be seen and given room to bloom in your finished fabric, then you can work both with the same size hook.

This is an example of why using yarn weight alone is not enough when substituting yarn.

Gauge is king (usually)

So after looking at all the weight and fibre considerations, I want to come to gauge.

I reiterate that for fitted items, gauge is crucial to make sure you make the same size as the crochet pattern is telling you you will.

Tip number six;

With yarn substitutions, it’s more important to match the the gauge in a crochet pattern (with a suitable drape) than it is to use a yarn of the same yarn weight and fibre.

Though the resulting fabric still needs to be fit for purpose of course.

I’d go as far to say that it’s better to work with a different yarn weight to that called for than to try and force a specific yarn to make the gauge.

What if I can’t match gauge?

If you are struggling to meet gauge but really want to use a specific yarn, there are a few things you could try.

To start with you can read more about what to do if you don’t meet gauge in this post and see if you can adjust your gauge.

If you can make gauge for the stitch count but not rows, then learning how to use the golden loop to adjust row height is incredibly helpful.

And bow for my final tip;

You can always find a yarn for a project and a project for your yarn…

Sometimes you just need to use a bit of creative thinking, trial and error (and did I mention swatch?)

As you can see. These 3 factors; gauge, weight and fibre, are interlinked, which is why it’s important to consider them all together rather than in isolation.

I encourage you to play around with changing up yarns and just see what happens. You might end up frogging it all and starting over, but sometimes you’ll find some unexpected genius…

I hope that this piece has been useful and has given you some tips on how to substitute your yarn in your crochet projects as well as given you a broader understanding of the considerations when selecting yarn for any project.

Happy Yarn Subbing!!!

Dx