How to work out how much knitting yarn you need for your project

Do you have a pattern or project in mind and want to substitute your own choice of yarn? Perhaps you are designing something and want to calculate how much yarn you will need.

Let me explain how I do it.

If you want to substitute yarn, not all yarns are the same, even if the weight of the skein and the thickness (Aran, DK, 4ply etc) is the same. For example, a 100g skein of DK  from different brands can vary in length by up to 15% because different fibres are different individual weights. Therefore, a lighter fibre will have more length to make 100g.

The first things to consider:

Knowing the length of 100g of the yarn you want to substitute will guide your choices and help you do a bit of maths!

Choosing the right Knitting yarn for your project:

Choosing the Right yarn for your Pattern:

It is difficult (though not impossible) to substitute a different thickness of yarn. So, start by looking at all the yarn choices in the same thickness (Aran, DK, 4ply etc) as your pattern/project

What knitting yarn does the pattern use?

Even old pattern yarns can be looked up on the internet! For example, if your pattern uses 600g of X double knit yarn to make a garment, and each 100g skein has 220m, your project uses 6 x 220m = 1320m. You will need 1320m of a substitute double knit yarn to make the pattern garment.

Next look at the tension recommendation for the pattern using the recommended yarn.  Double knit tension can vary, so check the tension (usually found on the skein label) of your potential substitute yarn. If it is similar or the same as the tension of the yarn used in the pattern you are a step closer to making your selection.

What is the fibre of my potential substitute yarn?

If the pattern uses an alpaca and silk yarn for example it will be quite soft and have drape, so substituting a cotton yarn will change the way the garment, looks, feels and wears because cotton doesn’t have any drape or stretch. Think about the finished item and how it will be used, look and feel and choose a yarn that will do that. If you are in any doubt, ask the yarn shop. They will know the most suitable yarns for the project you are planning.

If the pattern is for a hard-wearing item, for example, socks, although you could substitute alpaca and silk, it wouldn’t be very hard wearing. Your socks would be super luxurious but wouldn’t last long. So, think about similar knitting yarns that could be substituted rather than significantly changing the fibre type. Of course, if your item gets little wear, say a christening shawl, the pattern may call for a warm yarn but you could substitute as luxurious and soft a yarn as you like because the shawl will not be used very much, or for very long. (For children’s knitting, avoid yarns like mohair which are fluffy and can be a choking hazard if the child puts it in their mouth.)

What colour will you choose for your project?

What colour/s would I like?

Although the pattern may be pictured in blue, think about what colours you love, and what colours are available in the substitute yarns you have found. Don’t be tied to the colour in the picture, make your knitting project individual to suit you. Perhaps the garment is shown in a single colour but the yarn you like is multi coloured. There is no reason why you can’t substitute a multi-coloured knitting yarn if that’s the look you want. Just remember that if the pattern has complex stitch combinations, rather than being flat stocking stitch, you may not see the beauty of the stitch pattern with a multi-coloured yarn, and the colours will be broken up by the stitches. It’s all a personal choice, you may want a confetti-colour splash feel to your project and that’s great.

Hand dyed Yarns

I love hand dyed knitting yarns, and some of the choices of colour are stunningly beautiful and complex. Just have a think about whether all that colour will look the same on a garment. Speckles of colour on a plan base colour can be easier in an overall pattern than larger blocks of colour. It always amazes me how different a skein of yarn, the same skein wound into a ball, and then knitted can look. Perhaps that stunning, eye-catching colour could be a feature in a plain garment, for example a stripe of lime green or turquoise in a grey pullover if it would be too much as the whole garment.

DIY Daylight dye kits and hand dyed yarns

When using hand dyed yarns, it is advisable to use 2 balls at the same time, and knit 2 rows from one the 2 rows from the other. In this way you get less colour “pooling” where strong patches of colour on a skein can make a dense area of colour in your knitting.

Is your yarn choice sustainable?

What is your yarn made of? Where does it come from and how is it produced? How was it dyed and are there any other sustainability considerations with the care and repair of your finished project? (Here’s a link to our blog about washing your woolies….)How long will it last and still look good? Not sure? Have a look at the blog from last month, for more info on sustainable knitting yarn considerations.

Last thoughts:

Tension Squares

It can be a bit of a chore to knit a tension square before you start your project, especially when you are keen to get going. After all, you knit to average tension don’t you? You’d be amazed how much “average” tension varies, and it can make a big difference with garments and larger projects. The difference between a garment fitting well and looking a bit tight or a bit baggy. A tension recommendation on a pattern will look like 22 to 24 sts & 30 to 32 rows to 10cms (4″) square on 4mm needles. Tension is the number of stitches and rows measured over 10cms.

How will a tension square help?

If you knit a 6” x 6” square (or whatever the pattern recommends) you can tell if you have the correct number of stitches and rows to make the pattern come out the size it should. This is especially important if you are using a substitute yarn. Knit the square on the recommended needle size? Less stiches per inch than you should have? Your knitting is too loose and you need to try a smaller gauge needle. Too many stitches? Your knitting is too tight, try a larger gauge needle. Once your tension square, with the substitute yarn, is the same stitch and row count as the pattern, on whichever gauge needles you needed, you’re good to go!

Here’s our blog on getting the right size…..

Honestly, the only time I don’t do a tension square is if the item has no shape or it doesn’t matter if it finishes up bigger or smaller, for example a scarf. If I am making a garment I always swatch. I then use the swatch as spare yarn if I ever need to make a repair.

Knitting yarn substitution is easy when you know how, just a bit of maths to get the right one for  your planned project, a tension square to check and you’re on the way to making something unique and special.

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