Sport weight yarn is a fine yarn. (Not “fine,” as in “just OK,” but “fine,” as in “thinnish.” Sport weight yarn is more than “fine” in the other sense!) It’s slightly thicker than fingering weight yarn and slightly thinner than double knit (DK) weight yarn. Remember that “weight” in this context simply means “thickness,” and not actual, you know, weight. Why this is the case is another post for another time.
Sport weight yarn is often seen as interchangeable with DK weight yarn, but there is actually a subtle difference in thickness. If you’re planning on substituting one with the other, be sure to play around with needle size until you’ve got the required gauge for your pattern. Sport weight yarn is good for lightweight garments such as socks, mittens, hats, light sweaters, baby clothes, and shirts. It is also excellent for colorwork.
What’s on the label
Sport weight yarn is classified as a #2 yarn on the Craft Yarn Council’s standardized yarn weight system. This system was designed to create a universal standard for classifying yarn, and the world of yarn would be far more chaotic without it (thank you, Craft Yarn Council).
Please note that you will sometimes find a yarn that’s labelled as “Sport/DK”—this means that the yarn is thicker than some other sport weight yarns and thinner than some other DK yarns, so, as always, knitting a swatch to check your gauge is vital. Sport weight yarn is identified with a yarn skein icon featuring a 2 on the label.
The typical knitting gauge for a sport weight yarn is 23-26 stitches per 4 inches in stockinette stitch. Typical crochet gauge for single crochet is 16-20 stitches per 4 inches in single crochet. In both cases, we recommend trying your own swatch before starting your project to assess your natural tension (we’re really sounding like a broken record on this one, but please, save yourself headaches and do it).
The recommended knitting needle size for sport weight yarn is 3.25-3.75 mm (3 to 5 in US sizes). For crochet, a 3.5-4.5 mm (E-4 to 7) size hook is generally called for, but the recommended hook size will depend on what you’re making, so check your pattern, especially if you’re making a stuffed animal.
“Sport” is for “sportswear”
The name “sport weight” doesn’t refer directly to any kind of sport in particular, but rather to sportswear, inspired by Norwegian garments. In Norway, wool has been traditionally preferred for sports such as skiing and hiking because of its heat-retention and moisture-wicking properties. Knit from fine wool yarn in stunning geometric patterns, Nordic sweaters are famous the world over.
While the weight may have been named after sportswear specifically, keep in mind that sports weight yarn is highly versatile and can be used for a wide variety of projects.