Hey, You Asked! —What Do They Mean By a Yarn's "Weight"?

"When someone refers to the weight of a yarn, are they actually refering to the weight as in ounces or to the reference of sport, bulky, etc.? Which yarns are the heaviest/lightest?"

Yarn "weight" is all about the yarn's thickness. A lightweight yarn is a fine (thin) yarn; a heavyweight yarn is a thick (bulky) yarn. The tightness of the spin, the density of the strand of yarn, and the fiber from which it was created will all affect the weight of a yarn. Yarn weight is measured in YPP's (yards-per-pound), sometimes YPO's (yards-per-ounce), and in WPI's (wraps-per-inch). A yarn with a low YPP or WPI number (such as 250 YPP or 6 WPI) is considered a bulky, or heavyweight yarn. A yarn with a high YPP or WPI number (such as 1200 YPP or 18 WPI) is considered a fine, or lightweight yarn.

If a yarn is loosely spun with manmade fibers, and spun so that it has lots of "loft," and airspace between the fibers or strands, then that yarn will be considered a heavyweight, or bulky yarn, even if it doesn't weigh much (think Lion Brand Homespun). But take another fiber (such as New Zealand wool), and spin its fibers together tightly, maybe even plying it (twisting more than one strand together), without leaving much loft or airspace, and you have a dense, heavy yarn that may still be considered "lightweight."

"Worsted weight" is usually considered your average, middle-of-the-road yarn weight. Terms such as "sport weight," "fingering," "DK," and "light worsted" are all terms used for fine, lightweight yarns. "Heavy worsted," "bulky," "super bulky," and "rug" are terms used for thick, heavyweight yarns.

For more information (and a chart comparing yarn weights), click the link under Dux FAQs to read, Yarn Basics—YPOs, YPPs, WPIs.