Pattern Basics: Part 3 – Yarn Substitution

If you have been following along for the last two weeks, you know we have been talking about the different aspects of a crochet pattern. In Part 1 we covered the basics of reading through a pattern, troubleshooting areas that may be new to you and choosing the right size garment to ensure you get the best results. Part 2 covered information about gauge and the importance of this vital step. Today we’ll take a look how to substitute yarns in a pattern.

Experience has taught us that if a pattern specifies a #4 worsted weight yarn, substituting just any yarn with a #4 on the label does not guarantee pleasing results!  It is worth your time and investment to spend the effort required to do some research and swatching.

First, let’s briefly discuss why making a yarn substitution is tricky. When you find a pattern you want to make, part of what appeals to you is how the garment or project looks. The designer has spent a great deal of time finding the right combination of yarn, stitches, style, and shaping. That total look is most likely what made you love the pattern in the first place. So, when you make a yarn substitution, you are making enough of a change that the outcome may be dramatically different!

Here’s how to get the best results when you substitute yarns:

  • What is the weight of the yarn used in the pattern? The pattern should include the Standard Yarn Weight symbol. Look for the icon shaped like a ball of yarn with a number on the label. If the pattern does not have the icon look for key words like: Fingering, Light, DK, Medium, Bulky, etc. These are clues that you can use to match to the Standard Yarn Weights to help identify the yarn weight used in the pattern. When you look for a suitable substitution, look for a yarn with the same yarn icon or the same key words. For example, if your original pattern calls for a DK weight, look for the #3 Light icon or the words DK on the new yarn.


  • How many yards per skein? Within each category of Standard Yarn Weights, there is still a certain amount of variation due to fiber content, how the yarn is spun, etc. To get the most accurate substitution, pay attention to the yards per ounces/grams. For example, if the yarn in the pattern is a DK weight with 136 yards  per 1¾ oz/50 gram skein, you want to find a similar weight (ounces or grams) to yardage ratio, even if that means you are using a yarn that is put-up in a larger size such as a 3½ ounces/100 gram skein; in this case you would double the yardage and look for a skein with about 260-275 yds per skein. Remember, when subbing yarns, make sure you have enough yards for your project. For example, if the original pattern calls for 10 skeins of a yarn with 136 yards per skein, you’ll need a total of 1,360 yards of your new yarn. Because yarns differ so much, buying by weight (ounces or grams) could mean you run short or have too much yarn left over when your project is completed.

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  • What is the fiber content of the original yarn? Along with the above information, this step will help you get the best results. If the original yarn is a cotton and you sub an acrylic yarn even though it is the same weight and has a similar yardage, the results will be different. If it is possible, check the thickness of the suggested yarn in the pattern against the yarn you plan to use. Here’s a quick test to see if they are similar: fold each in half looping the 2 yarns through each other. Run your fingers over the double-thickness of both yarns; your sense of touch will tell you if they are a similar thickness.

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  • Finally, spend some time working a gauge swatch with your new yarn to see if you are happy with the resulting fabric. Will it work for the pattern you have in mind? Is it too stiff for a garment or too wimpy for that afghan pattern you want to use? Keep swatching until you are happy with the results and you have matched your gauge to the pattern’s gauge.

Following these simple steps will save time and effort when substituting yarns. For more information you may want to check out this previous blog post. Happy Crocheting!

2 responses to “Pattern Basics: Part 3 – Yarn Substitution”

  1. I need to change a crochet pattern calling for #2 Sport, Baby yarn to using a #4 Worsted weight yarn. How do I do this? Is there a conversion chart or must I make a swatch and figure out the size differences? Then what do I do?

    • Unfortunately there isn’t a straight answer that I can give to this. Yes, you probably can change it. The size will be different and the amount of yarn will change. There isn’t a conversion chart that I know of. You would need to swatch and then do math to rework the pattern. There are some sites if you do an online search that will give advice on how to rework the math of a pattern for a different yarn. It will just take some looking.

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