Medium-weight yarns are also known as worsted weight yarns. They’re slightly heavier than lightweight yarns, and are typically used for projects such as afghans, sweaters, and hats. Aran weight yarns are slightly heavier and are sometimes referred to as heavy worsted. Think of worsted weight yarns as “all-purpose” yarns, since you can use them for so many different types of projects.
Stitches per inch: Knit 4-5, Crochet 3-3.5
Needles: US 7-9; Hooks I9-K10.5
Wraps per inch 10-12
Yards per 100 Grams: 218-262 (Aran 131-174)