How to Choose a Substitute Yarn

Are you a knitter who has ever felt lost when it comes to choosing the perfect yarn for your project? Or maybe you’ve found the perfect pattern, but the recommended yarn isn’t available or doesn’t fit your budget. Fear not! In this blog post, we’ll walk you through the steps of choosing and substituting yarns, so you can create the perfect piece every time. 

First things first, look at the weight of the yarn.  Patterns usually suggest a specific weight of yarn such as 4-ply, double-knitting, Aran-weight or chunky.  Substituting with a different weight yarn than that suggested by the pattern can change the look of a garment dramatically, so it is best to choose a yarn of the same weight or ply.   A yarn ball band will contain details of the weight.  The weight of the yarn, in addition to the needle size you use and the tension or gauge that you knit in, will determine the size of your stitches and the overall size of your finished project.

The knitting term ‘gauge’ (sometimes also called ‘tension’) simply means the number of stitches and number of rows over a 10cm square.  One of the principal factors that can alter the gauge is the yarn you choose.  The needle size, the stitch pattern and even how you knit, whether you knit with the yarn held tightly or loosely, can also affect the gauge.

If you’re substituting a yarn, it can be useful to look at the ball band information for the recommended yarn suggested in the pattern and compare it to the yarn you are thinking of substituting it with.  Swatch with the new yarn and adjust your needle size until you achieve the correct gauge. Remember, gauge swatches are essential to make sure that your finished project will be the correct size.  

Comparing the recommended needle size on a ball band with the pattern recommendations is also a good guide to whether a yarn will be suitable for a pattern.  Different needle sizes are recommended for different weights of yarn, for example a 4-ply weight yarn is typically knit up on 3mm or 3.25mm knitting needles whereas chunky wool is usually knit up on 6-8mm knitting needles.   When choosing a yarn, the suggested needle size is particularly important, as it will give you an idea of the thickness of the yarn and whether it will be a good fit with the pattern you have chosen. 

Another way to ensure that the yarn you choose is comparable to the yarn suggested in the pattern is to compare the meterage per gram.  The number of metres and number of grams of yarn in a ball will be included in the ball band information.  To find the meterage per gram, divide the number of metres by the number of grams, so if the ball is 100g and the number of metres in the ball is 298m:

298 / 100 = 2.98 metres per gram

If you have chosen a yarn that is in 50g balls, then for the above example, a meterage of between 140m and 160m per ball would be a good match with the suggested yarn in the pattern:

50g x 2.98m/g = 149m

As a general rule, balls of wool of a similar fibre, for instance Acrylic, in addition to a similar yarn weight, for instance double-knitting will have a similar meterage per gram.

Next, consider the fibre content of the yarn. Different fibres have different properties, and the fibre content of your yarn will affect how your finished piece looks and feels, for example, wool yarns are warm and stretchy.  Acrylic yarns, although less expensive and easier to care for than wool, don’t have the same softness and drape.  When choosing a yarn, think about the qualities you want your finished project to have and select a fibre content that will achieve that. 

Lastly, consider the colour and texture of a yarn as this will play a key role in the appearance of your finished project. Consider the stitch pattern and the overall look you want to achieve when selecting a yarn.  You may want to choose a solid or variegated color, a smooth or textured yarn, or a yarn with a sheen or matte finish. When substituting a yarn, keep in mind that the finished project may look different than the original pattern due to the differences in the texture of a yarn.  For example, there is less stitch definition with an alpaca yarn than a merino wool yarn.