If you're interested in knitting or crocheting, knowing how to buy the right kind of yarn for your project is crucial. When you're working with the wrong yarn for a particular pattern, it's going to be either difficult or impossible to get the correct results. One of the factors to consider when choosing yarn is the yarn ply.

Essentially, yarn ply refers to the number of strands that make up your yarn. During the manufacturing process, different strands are twisted together to form yarn. If you untwist these strands, you can count the yarn ply. For example, two-ply yarn has two separate strands and three-ply yarn has three separate strands.

A good rule of thumb is that yarn with a higher ply count results in more stitch definition. So, if you want to see cables and texture in the final project, higher ply yarn is a good choice. However, if you like a rustic, cozy, or homespun effect, yarn with a lower ply count may be a better option. In addition, yarn with a lower ply count tends to blend different colors together, resulting in a very pretty watercolor effect.

One advantage of working with a higher ply yarn is that the act of twisting strands together can help to correct the tendency of the yarn to slant as you're knitting or crocheting. When knitting with a lower ply yarn, you might notice that your stitches look more like a lopsided check mark than the neat "V" shape you expected. If your yarn is extremely unbalanced, your entire swatch may even seem to tilt to one direction.

Another factor to consider when choosing the yarn ply for your project is durability. Generally, yarn with a higher ply count is more durable. The process used to create the plies keeps the fibers tightly wound together. As a result, projects knitted or crocheted from yarn with a high ply count are less likely to pill, shed, or wear thin when washed.

It might seem like yarn ply would be directly related to yarn weight. However, a yarn with four plies is not necessarily thicker than a yarn with only two plies. If the individual strands are very thin, even having several strands twisted together might not result in a very thick yarn. One simple way to measure the weight of your yarn is to wrap it around a ruler, then count the number of wraps per inch. Yarn weight is also listed on the label that comes with your yarn, ranging from 1 (super fine) to 6 (super bulky).