Many times a knitter will select a pattern to knit only to discover that the yarn used in the pattern is either not available or there isn’t a sufficient quantity available for purchase or it costs more than what the budget allows. So, that leads to finding a reasonable substitute to use. I have seen many forum posts in Ravelry where knitters have had difficulty making a proper substitution.

The first step in substituting one yarn for another is to look for a yarn of similar fiber composition that has approximately the same weight and recommended gauge as the yarn listed in the pattern. By this, I mean if the yarn used in the pattern is worsted weight (size 4), it’s best to find another worsted weight yarn to use as the substitute. If you are purchasing from a local yarn shop, the staff may help you find a substitute. If shopping online, Yarnsub.com is a helpful website that can be used to guide your initial search. Another resource is Ravelry – if the pattern is available in the Patterns database, you can look at others’ projects to see what yarns have been used. Regardless, once you pick your substitute yarn – you’ll need to swatch to find your gauge before you cast on and begin knitting the pattern.

Question: “I’m not getting the same gauge with my substituted yarn as the gauge stated in the pattern – what do I do now?

Here are some options to consider:

1. Change needle size and reknit the swatch to see if you can match the gauge. If you are getting more stitches than the stated gauge – go up one or two needle sizes. If you are getting fewer stitches than the stated gauge – go down one or two needle sizes. If you succeed in matching gauge with the change in needles and you like the fabric you are producing, then simply follow your pattern and knit with the size needle that helps you get gauge.
2. If you still can’t get gauge after changing needle sizes, but you like the fabric you are getting, calculate the number of stitches you need to cast-on to match your chest measurement and check the pattern to see if there is a size that uses the same number of stitches. You may still need to make adjustments in shaping if your row gauge is different from the pattern.
3. Use the pattern as a guide only – use the schematic plus any adjustments you need to make and then determine the stitch counts and rows needed to make the garment with your own gauge. (A good reference for this is Knitting Pattern Essentials by Sally Melville)

Here’s the next issue for substituting one yarn for another: Does the substitute have the same weight and yardage as the original yarn? If it does – you are in luck and can simply buy the same amount of yarn as what is given in the pattern for the size of the garment you want to knit. (Remember to buy an extra one for swatching.) However, in most cases there is a difference in yardage and/or weight between the substitute and the original yarn – which leads to the question: “How much of my substitute yarn do I need? This brings us back to the basic math I covered in my previous post: “To determine the number of skeins, balls or hanks of yarn you need: Divide the number of yards by the number of yards in the skein. Or divide the total number of grams by the number of grams of the skein.  Remember that you will want one extra skein for swatching. “