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YARN SUBSTITUTION CALCULATOR

(That's right - no more yarn chicken!)

Choosing a different yarn for your knitting or crochet project doesn't have to be confusing.

One of the biggest mistakes makers make is comparing the number of balls a pattern uses instead of the total meterage (or yardage). Two yarns may both come in 100g skeins, but if one contains 400 metres and the other only 300 metres, you'll need very different quantities to finish your project.

Our free Yarn Substitution Calculator does the maths for you. Simply enter the details from your pattern, alongside the yarn you'd like to use, and we'll estimate how many skeins you'll need. Whether you're shopping your stash, choosing a luxury alternative, or substituting yarn that's no longer available, this calculator helps you choose with confidence and avoid running out halfway through your project.

Step 1 - Yarn Category

Make sure the yarn you wish to substitute is in the same yarn weight category as the original yarn (i.e. 4ply, DK, Aran etc)

Some yarns don't specify their category on the label, but will give tension / gauge information. For example: 22sts = 10cm / 4 inches.

If your yarn label gives a tension +/- 1 stitch of the tension specified in the pattern then continue to Step 2.

Step 2 - Fibre Content

Now we need to take a look at fibre content. A 100% alpaca yarn will behave very differently to a 100% cotton yarn, so this needs to be considered when looking at suitable yarns for your pattern.

Does the design call for structure or drape? Is it heavily cabled, plain stockinette, or does it have lace details?

A good rule of thumb is to stick closely to the fibre content of the original yarn used in the pattern.

Step 3 - Punch the Numbers

Enter all the yarn details into the calculator below.

We substitute by length and not by number of balls / skeins, to ensure you don't end up playing a stressful game of "yarn chicken" towards the end of your project!

Please note that calculations are based on the pattern being knit to the tension / gauge specified.

Yarn substitution calculator

Calculate how many balls / skeins of substitute yarn you need, when using an alternative yarn to the one specified in your pattern.

Original Pattern Details

Total metres needed

Substitute Yarn Details

You will need:

Need help choosing a substitute?

Our team helps knitters find suitable replacement yarns every day. If you're unsure whether a yarn is a good match, simply send us the pattern details and we'll send you some yarn options from the selection on our shelves.

Ask Our Yarn Experts

Why trust our advice?

We've been helping knitters choose yarn since 2006. Every day we help customers substitute discontinued yarns, choose alternatives for patterns from around the world, and work out how much yarn they'll need before they cast on.

We also share helpful tips, alongside special offers and new product updates through our weekly newsletter.

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Find Yarn by Weight Category

Clarendon Sock | Townhouse Yarns - This is Knit
4ply
Spiral Grain Sport | Urth Yarns - This is Knit
Sport Weight
Ricorumi Yarn | Rico Design - This is Knit
Double Knitting
Aran Weight
Big Merino | Katia - This is Knit
Chunky
Millenium | Rosarios 4 - This is Knit
Super Chunky

Yarn Substitution Calculator FAQs

Absolutely. The calculator works for both knitting and crochet patterns.

Yes. Weight tells you how heavy the yarn is, but meterage tells you how much yarn you're actually getting. One 50g ball of cotton, for example, will contain less metres than 50g of wool. This is because cotton is much more dense than wool.

When substituting yarn, matching the total metres or yards is usually the best starting point.

Because yarn balls come in different lengths. A 100g ball might contain 200 metres while another contains 400 metres. The total meterage is what determines how much knitting or crochet you can complete.

When substituting yarn, always compare the total meterage (or yardage), not the number of balls or the weight of the skeins.

Both meterage and weight category have an impact when you are considering substituting yarns. The yarn weight category (e.g. 4ply/fingering tells you roughly how thick the yarn is, but meterage tells you how much yarn you're actually getting. When substituting yarn, you need to bear both criteria in mind.

No. It provides a reliable estimate based on yarn length. You should always knit a gauge swatch and check the pattern requirements before beginning your project.