Good to know – How much yarn will I need if …?

How to determine the quantity of yarn.

Lately I’ve often had to answer the question how much yarn you need if you want to replace yarn A used in the instructions of a pattern with yarn B. I would therefore like to tell you what problems I had with it at the beginning and how I now calculate my individual yarn needs.

Usually, the yarn used and the amount required are included in the pattern. So far so good. The problem often starts when you want to use a different brand or – even worse – a different weight of yarn for your project.

Different Yarn weights – my nightmare

All the different yarn types, weights and yardages can be very confusing. I still remember well when I started to crochet again about 10 years ago I was helpless when it came to choosing the right yarn. Foreign patterns mostly call for foreign yarns. Brands like Stylecraft, Scheepjes and Caron, to name only a few, are not available in our retail stores. So I had to replace them with other brands. There is also no system in Germany that classifies the different yarn weights. Only in the last few years the American system has been adopted by some companies. So I really was lost since I had no idea what was meant by terms like DK, Aran, Sport weight, fingering and so on.

At the beginning I thought that the needle size indicated on the banderole was decisive. Believe me, it isn’t.
Choosing a yarn after that often meant that I had too much or too little yarn and that my crochet piece was not the desired size as my yarn was too thick or too thin.

After I went wrong several times, I started ordering my yarn in foreign online shops to get exactly the yarn that was required in the pattern. That’s when I discovered that there is a system abroad that divides yarns into different groups.
It was only after I had dealt a bit with the different yarn weights that I realized that the thickness of the yarn also influences the length of the thread. Actually logical, a thinner thread has to be longer to bring the same weight on the scale, a thicker one will be shorter.

As an example:

A DK yarn has a yardage somewhere between 240 and 300 m per 100 g ball, and Aran only 120 – 240 m for the same weight.

Knowing this I changed my personal system to choose a suitable yarn. When I shop in Germany and the yarn banderole does not indicate what thickness it is, the yardage helps me. A 50 g ball with 145 m per 50 g for instance is a DK weight as it will have 290 m per 100 g.

But I learned more. The yardage is also helpful if I want to use another weight than specified in the pattern. Here an example:

Changing yarn weights

Let us say your pattern calls for 3 balls of Stylecraft Special DK but you would like to use Aran because you like your piece to be a little thicker. 3 balls Special DK are 300 g but if you buy 300 g Aran you will definitely have too little yarn. How much will you need then? I calculate it with the help of the yardage.
Just look at the amount of yarn that is required in the pattern and calculate how many meters or yards it will be. To do this, multiply the number of balls by the length of one ball. This gives you the total yardage you need.

Now look at the yarn you want to use. What is the yardage of one ball? Divide the total yardage you worked out before by the yardage of a ball of your desired yarn and you will know how many balls you will have to buy.

If more than one colour are required just repeat this for each colour.

I never went wrong this way!

In a pattern the information on the length of the thread should be given together with the information about the yarn used. If this information is missing, just search for your yarn in the internet or look at your yarn banderole (if you have them at hand).

But please keep in mind that changing the yarn weight will affect the size of your project. I would advise not to do it for garments like sweater and so on as long as you don’t know how to adjust the pattern.

I hope this was helpful to you 💕