Yarn Substitution Calculator

When we knit and crochet we often want to use yarn that’s different to what is specified in a pattern. Many think that the weight of a ball is what makes the difference, but one ball weighing 50g may have much more, or less, in length. So, when substituting yarns, make sure you know the LENGTH of the yarn in a ball so you can calculate accurately.

Figuring out how to do that can be tricky, so we’ve created a handy calculator to help you do that really easily. Aren’t we nice? :)

To be able to calculate correctly, you need this information:

  • How many balls of each colour does the pattern say you need? 
  • The pattern tells you which yarn to use. Sometimes it tells you the total meterage you need of each colour but most of the time it doesn’t, so you need to look up that yarn and find out how many meters are in each ball. Ravelry is a really handy place to find most yarns, or good old Google!
  • Now look at the ball that with you want to change the yarn. How many meters is listed on that yarn? 

The calculator will calculate the following:

  • How many meters the project requires by using the meterage on the suggested yarn and multiplying by the number of balls required.
  • It will then factor in the new meterage on the ball to which you want to change. It will cross-compare the meterage and give you the numbers of balls of the new yarn that you need.  Et Voila! 

Yarn Substitution Calculator for Projects

How much yarn will you need for your project? This calculator will figure out yarn quantities when substituting your yarn.

(please enter only numberical values)


Remember, when you substitute yarn from one class weight to another, the thickness of the yarn will change the amount of yarn used per stitch. This has been created for those who are substituting yarns within the same class. There may be some degree of variance.