Every now and then I can not use the yarn that is suggested in a pattern. Either because I can not buy it in my country (or would have to get it shipped a long way, which I try to avoid) or because I can not afford the suggested yarn. Then I will try to find a good substitute for the suggested yarn. This is how I do it:

Some yarn labels with information about the fiber type, yardage and weight.
Examples of how the fiber type, yardage and weight can be described on a yarn label.

Step 1 - Similar yardage per grams

The yarn I want to use as a substitute must have similar weight and yardage values as the suggested yarn in the pattern.

So the first thing I do is to check how many meters / yards the suggested yarn has and how much one skein / ball / hank / etc. weights. The information I am looking for is usually described somewhat like this:

More examples can be found in the image above.

It really does not matter how this info is given as long as I find both the weight and the yardage. Now compare the suggested yarn and your possible substitutes regarding these values.

Here is an example

The yarn suggested in the pattern has 50g and 120m and I have the following yarns to choose a substitute from:

Yarn option 1 has 100g and 240m.
➞ This one would be a perfect match and a really good choice.

Yarn option 2 has 50g and 300m.
➞ I would not want to use this yarn, because it is way too thin, i.e. it has too many meters per 50g

Yarn option 3 has 50g and 50m.
➞ This yarn is not a good choice since it is way to thick, i.e. is has too few meters per 50g.

Yarn option 4 has 100g and 220m.
➞ This yarn will most likely work fine as a substitute, because it has 110m per 50g which is only a little less than the suggested yarn.

(If you are interested: I do not use the yarn weights like "lace", "fingering", "worsted", "bulky" etc. for comparison. There are two reasons for that: (1) In Germany (where I live), we don't use yarn weights. Our yarns do not have named categories like that. (2) In my experience comparing the values for weight and yardage is more accurate than comparing yarn weights, since people seem to classify them in different ways.)

Step 2 - Similar fiber type

The next thing I do is comparing fiber types. Once again the goal is to find a yarn that has the same (or very similar) fibers as the suggested one.

Why is that necessary? Because the characteristics a fiber has, have a huge impact on the design. If you use a completely different fiber than the suggested one, you might get a garment that has the right size. But that could also be all you get. The whole feel to the garment, the drape, the clarity of the stitch pattern, even the fit and so much more can be completely different to the shown sample. As a designer I think the fiber used is often key to a design.

The yarn label will let you know what fibers a yarn is made of. You can then compare the fibers of your substitute to the fibers of the suggested yarn.

Here are some examples, on what could work and what might not:

The suggested yarn contains mostly cotton, linen and / or viscose.
➞ In this case I also want to use a yarn that contains plant fibers. Using a 100% alpaca yarn or pure mohair would be a very bad idea in this case.

The suggested yarn contains mostly wool, e.g. merino.
➞ Then you do not want to use a 100% cotton yarn, while using a different kind of wool with a second strand of silk mohair is probably working very well.

A good rule of thumb is not to substitute natural fibers with synthetic fibers and not to replace animal fibers with plant fibers.

The key to decide if you can use a yarn as a substitute is knowing the characteristics of the different fibers. Of course listing all fiber types here for comparison would go way beyond the scope of this text. Just do some research. You can find the info all over the internet.

Step 3 - Gauge and feel of the fabric

When I have found a yarn that meets the first two criteria, I usually start to swatch. I still need to know if I can get gauge with the yarn I chose. Some general tips on swatching you can find in my Swatching Guide.

But when I substitute yarn there is one more thing I want to pay very good attention to:

I want to make sure that the fabric I created from my substitute yarn has the right feel to it. What do I mean by that? I want my fabric to behave in a similar way to how I think the sample in the pattern behaves.

Let's have some examples:

My project is a summer shirt that is all airy and drapy.
➞ In this case I do not want my swatch to be super dense and stiff, but flexible. There is a good way to test that: Hold your swatch horizontally between the tips of thumb and index finger. If your swatch stays almost flat and horizontal when you hold it like that, then the yarn is not a good substitute.

My project is a pointy hat, that is supposed to have a good stand.
➞ In this case the swatch I described in the previous example would be perfect. But I don't want to use a yarn that creates a swatch that is super flexible and wraps itself around my fingers while I hold it.

And well that is it! These are the three steps I take, when I want to use a different yarn for a project. I hope you found this helpful!

Warm regards and happy knitting!