Worsted weight yarn is a medium weight yarn that sits in the middle of the yarn weight family. It is thicker than sock and sport weight and thinner than bulky weight yarn. Worsted weight yarn is considered a medium weight number four yarn with a knitting gauge of 16-20 stitches for every four inches of knitting. It is ideal for projects with a knitting gauge of 4-5 stitches per inch and a crochet gauge of 2.75-3.5 single crochets per inch. Most worsted weight yarns have a WPI (wraps per inch) of between 9 and 12. Worsted weight yarn is great for knitting sweaters, hats, scarves, mittens, blankets, and beyond. It is strong and durable, making it ideal for items that will get a lot of wear, like sweaters, scarves, afghans, and hats.