Double knit (DK) weight yarn is a medium-fine yarn, also sometimes referred to as a light yarn or light worsted yarn. It’s thinner than a worsted weight yarn but thicker than a sport weight yarn.
NOTE: It’s important to remember that “weight” in this context has nothing to do with the actual weight of the yarn and everything to do with how thick or thin the yarn is. Consider getting weight = thickness tattooed somewhere prominent on your body, so you never forget (Just kidding. Please don’t do that).
Two strands of double knit (DK) weight yarn tend to be approximately equal in thickness to a single strand of worsted weight yarn and can be used as a substitute for worsted weight yarn in a pinch. DK yarn is a great, versatile yarn which is ideal for lighter pieces like baby blankets, spring sweaters and shawls.
According to the Craft Yarn Council’s standardized yarn weights chart, double knit (DK) yarn is a #3 (light) yarn. The Craft Yarn Council is an organization that brings together representatives from all areas of the craft yarn industry. Their yarn standards were created “to bring uniformity to yarn, needle and hook labeling, and to patterns, whether they appear in books, magazines, leaflets or on yarn labels” and their system is considered the universal standard. You’ll generally find an icon featuring a skein of yarn with a number 3 on it on the label of a DK weight yarn, along with other information and icons pertaining to gauge and needle size.
The knit gauge range for DK weight yarn is 21-24 stitches = 4 inches in stockinette stitch. For single crochet the gauge range is 12-17 stitches = 4 inches. Always check pattern recommendations and/or make a sample swatch to check your natural gauge.
The recommended knitting needle size to use with a DK weight yarn is 3.75-4.5 mm metric (5-7 US). Your ideal choice of crochet hook size will depend on your project and personal taste, but the Craft Yarn Council generally recommends a 4.5-5.5 mm hook (7 to I-9). For stuffed animals or amigurumi, consider a 3 mm hook, which will give you a tighter fabric that is less likely to show stuffing.
While DK weight yarn is easy to use no matter your level of experience, it shares a name with a knitting technique that may cause confusion. Double knitting is creating two layers of knitted fabric with a single pair of needles. This knitting technique has nothing whatsoever to do with DK weight yarn and while DK weight yarn could be used for double knitting, the technique does not require it. DK weight yarn is an ideal all-purpose yarn that can be used for any number of patterns.