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Measuring Your Treasure

Often in schools we are given odd balls of yarn with no labels, and we therefore don't know what size it is or what fibre it is made from. Likewise when we spin our own yarn we don't know the gauge. For many projects this doesn't matter, we can just finger knit or weave our yarn without worrying about how much we have or how thick it is.

However, if we want to follow a pattern, or work out if we have enough yarn to complete a project, we need to find a way to calculate yarn gauge and length. I will talk about ways to calculate length in a future post. Below is my lesson on calculating yarn gauge.

Calculating Yarn Gauge

Age of child: Any

Materials: A ruler that measures in inches, balls of several different weights/gauges of yarn, both with and without labels.A yarn gauge if possible (otherwise print the picture of a yarn gauge)Yarn gauge chart printed and laminated to be kept on the handwork shelf.

Text in italics: what I say

Standard text: what I do

Step 1.

We have all of this beautiful yarn here and we can think of all sorts of wonderful projects to make with it. But before we can make our plans, we need a bit more information about the yarn.

The first thing we need to know is how thick the yarn is. This will help us choose what size knitting needle or crochet hook to use and know what sort of patterns the yarn is suitable for.

The yarn thickness is called its gauge. If we have bought commercial yarn for a project it is easy to tell what gauge it is, as it says it on the label.

Examine some yarn labels with the children, discuss the gauge and whether the children think this means the yarn is thick or thin.

Look here, this says it is……. and even tells us that it would be best to knit with size….needles. This is very helpful.

Step 2.

But if we have spun our yarn or it doesn’t have a label we won’t know what gauge it is so we have to work it out. We can calculate the yarn gauge by finding out how many strands of the yarn we can fit in the space of an inch. We call it Wraps Per Inch or WPI.

Note: If you are used to working in the metric system, you will have to explain what an inch is. Even in metric countries, yarn is calculated using an inch. This links well to Geometry and Maths.

Let’s have a look at our ruler. Each of these lines is one inch apart so if we wrap the yarn around it as many times as we can between two of these lines, we will know how many strands of the yarn we can fit in the space of an inch.

I’m not going to use the first inch as the yarn might slip off, I’ll try to wrap the yarn on the second inch of the ruler. I’ll use my thumb to make sure the yarn stays within my inch.

Begin to wrap yarn around ruler as described.

I don’t want to make it too tight, or too loose, and I don’t want to squish it up too much – I just want each strand to sit comfortably side by side without feeling stretched or squashed.

When you have filled the inch, use a thumb on each side to keep the wraps in place and ask the children to confirm that you have comfortably filled your inch.

Step 3.

Okay, we have wrapped our yarn onto our inch – let’s see how many wraps we have.

Let the children count the number of wraps within the inch e.g. 9

Our has nine Wraps Per Inch, we call that 9 WPI. If you called it that most spinners would understand but we also have names for each gauge of yarn. Different cultures have different names for their varieties of yarn. We have a table here that will help us find the name of this yarn gauge

Show the children the WPI table and identify the yarn you have just measured on it.

Our yarn is 9 WPI so it is called Worsted (or Medium in USA).

Now that we know this we can look for a pattern that calls for Worsted yarn.

Step 5.

Did you notice that when we were wrapping the yarn around the ruler I had to use my thumbs to keep it in place? It was a little bit fiddly wasn’t it? And even though we had the whole ruler we only needed one inch of it. Well spinners have a special tool to figure out WPI that is slightly less fiddly to use than a ruler. It is also smaller than a ruler so it can fit in a spinners basket or bag more easily.

Let’s measure the space that is cut into it…..

Use ruler to measure space.

It is one inch. Freya, would you like to try wrapping our yarn in the space?

Allow children to wrap yarn around gauge, discuss ease of use.

This is called a Yarn Gauge. Remember we said that the yarns thickness is called its gauge, now we have found that the tool we use to measure it is also called a gauge – the word gauge can do more than one job!

People have made yarn gauges out of all different materials – some of them are very beautiful.

Show pictures of different yarn gauges. Notice that they all have a one inch notch.

photo by Katy Westcott and
Photo by Duarte Made, LLC
Photo by NiddyNoddyUK on

If you like you could make your own yarn gauge out of materials we have in the class.

Discuss materials available to make yarn gauges (cardboard, ice-cream lids, clay).

Children can measure all the odd balls in the class and make beautiful labels for them.

They can also test to see what fibres the yarn is made from, but that's a story for another day!

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