What is WPI and how does it help in yarn crafts
WPI stands for Wraps Per Inch, it is a method of measuring yarn weight. It is a simple tool but quite useful for yarn crafters. For hand spinners a WPI tool is particularly helpful in determining the weight of your handspun.
A 3D printed WPI tool with pink yarn wrapped in the 1-inch groove.
To find out a yarn weight, simply wrap a strand of yarn around a ruler, taking care not to stretch the yarn nor wrapping it too loosely; wrap the yarn around the ruler for 1 inch or 2.5cm, making sure each strand is touching each other but not squashed nor there are any gaps in between. Then count the number of wraps to get the WPI. Using the photo above as an example, there are 16 wraps in total, which makes it a Fingering weight yarn or 4ply.
The sample in the above photo is a WPI tool, designed specifically for this purpose. The groove is exactly 1 inch or 2.54cm.
There are many instances where a WPI tool is useful:
spinners can use this tool to determine how their handspun will turn out while spinning (this deserves its own post with more detailed explanation);
spinners can use this tool to determine the yarn weight of their handspun after the yarn is finished;
knitters and crocheters can use this tool to find appropriate yarn alternatives that differs from the pattern;
or when you need to determine the weight of a mystery yarn that has lost its label
Once you have wrapped and counted, you will need a chart like the one below to help you find the corresponding yarn weight. There are quite a few yarn charts available online, each is slightly different to another. The chart below is one I have modified myself based on my own experience of spinning, knitting, crocheting, etc., over the past twenty year. It’s by no means exhaustive nor authoritative, it’s just a tool that helps me in my crafts.
A chart showing WPI counting with corresponding yarn weight.
You don’t need any fancy tool to count WPI, any ruler will do. But these 3D printed little WPI tools are so cheerful and lightweight, and so easy to use, it’s really hard to say no to such little delights. I’m sure they will help brighten up your day ☺️
Colourful 3D printed WPI tools.
