Choosing a suitable yarn

Choosing a suitable yarn for your knitting project is dependent on many factors such as what the knit is used for, the wanted smoothness and your color preferences.

If you're searching for a yarn suitable for a specific pattern and want to use a different yarn than the pattern uses you need to take note of a few things.

First you should compare how much yarn there is per skein in the replacement yarn, in other words, how many meters per 100g there is, for example 200m/100g. The replacement yarn is suitable if it's around 20m/100g more or less than the original. 

If the yarn has an approximated gauge, meaning stitches per 10cm, you should compare it to the gauge given in the pattern. If both these factors match with the original yarn used, it's pretty safe to say that you can use the replacement yarn for the pattern.

Many patterns give the amount of yarn used for the whole knit for example 840m. This can be divided by the meters per 100g of the replacement yarn, so the equation should come out to the needed amount of skeins. So 840m/200m=4,2 skeins, in which case you should get 5 skeins for the whole knit.

If you are unsure whether the replacement yarn is suitable, you should knit a test patch. With it you can determine your stitch density and calculate the appropriate stitch amount. You also get to test how for example a specific color combination or lace knit will look. You should also wash the test patch by hand or machine depending on how you'll finish your knit. With this you can also test whether the yarn is suitable for machine wash, washing the test patch in the wool setting of your washing machine.

Yarn consistency can also be a huge factor in the properties and look of a knit.The properties will change as you change the yarn. For example the smoothness will change with wool or plant fiber yarns.

A rule of thumb could be that thin yarns are good for indoor use and thicker ones are good for outdoor use and socks and other heavy use knits.