Guide
Choosing the right yarn is half the job. Here is an overview of the most common fiber types and what they are best suited for.
Quick answer: Fiber content determines how warm, heavy, elastic, and durable your finished garment will be – often more than the color or the pattern itself. Use the lexicon below to find the fiber that fits your project, and read on for tips on natural vs. synthetic fiber, blends, and yarn care.
A Norwegian version of this page is available on Strikketips.no
When picking yarn for a new project, it's easy to stop at color and price. But fiber content matters just as much, because it determines how the finished piece behaves – both while you knit it and for years afterward. A sweater knit in alpaca will stretch and sag over time, while the same pattern knit in wool holds its shape far better.
Ask yourself a few questions before you decide: Will the garment sit against the skin, or is it outerwear? Does the pattern rely on elasticity – cables or ribbed edges that need to stay snug? Does it need to survive the washing machine, or is hand washing fine? Do you or the recipient have a wool allergy? The answers will quickly point you toward the right fiber family.
Yarn is generally grouped into four origins: animal-based (from animals, like wool and silk), plant-based (from plants, like cotton and linen), regenerated (plant pulp chemically dissolved and spun anew, like viscose made from bamboo), and synthetic (made from petroleum products, like acrylic, polyester, and nylon/polyamide). Regenerated fibers are easily filed in the wrong drawer: the raw material is a plant, but the fiber is made in a factory. Natural fibers breathe, regulate temperature, and often feel more luxurious against the skin, but they typically cost more and need gentler washing.
Synthetic fibers are cheaper, highly durable, and usually machine-washable without shrinking. They are also an option for knitters who cannot wear wool next to the skin — we do not call them allergy-friendly, since that is a health claim we have no basis for. The downside is that they breathe less well, can feel "sticky" against the skin on warm days, and do not break down the way plant and animal fibers do. In practice, acrylic and nylon are rarely used alone for an entire garment, but they often show up in blends to add durability – especially in sock yarn.
Many of the most popular yarns are blends, because blending lets you combine the strengths of two or more fibers. A classic example is sock yarn, which is often around 75–80% wool and 20–25% nylon. The wool provides warmth and comfort, while the nylon lets the heel and toe withstand the friction from shoes without wearing through.
Silk is often blended with mohair to tame its airy "halo" and add shine and strength, while wool and alpaca are combined to get alpaca's soft warmth without the garment losing all its elasticity. Always read the fiber content on the yarn label – the percentages tell you a lot about how the yarn will behave, even when the yarn's name doesn't spell out every fiber.
Sheep wool is the fiber most knitting yarns are built on — 28 of the 31 yarns in our own Norwegian brand guide contain wool or merino. It is naturally temperature-regulating, breathable, and can absorb significant moisture without feeling wet.
Extra fine wool from Merino sheep. The fibers are thinner and crimpier than regular wool, making it extremely soft and non-itchy against the skin.
Alpaca fiber is essentially free of lanolin (wool grease), which is why many people find it gentler against the skin than sheep wool. It is extremely soft, but lacks elasticity and stretches out of shape more easily than wool.
Fiber from Angora goats. Known for its silk-like luster and "halo" (fuzzy surface), and the fibers are stronger than wool fibers. In knitting yarn it usually appears blended with silk or wool.
The undercoat of the cashmere goat, gathered by combing or shearing in spring when the goat sheds. The fiber is very fine and gives warmth out of all proportion to its weight. It has little elasticity, so pure cashmere loses its shape more easily than wool and should be stored flat.
Fiber from the Angora rabbit — not to be confused with mohair, which comes from the Angora goat. The fiber is very soft, fine, warm and light, with a pronounced halo. Lower-grade angora sheds, and the fiber is often blended with wool.
The undercoat of the yak, a domestic animal of the Tibetan highlands and the ranges around them. The animal is an even brown with a silver-grey stripe along the back, and many yarns keep that natural colour undyed. In our experience yak yarn feels soft without losing its shape as readily as pure cashmere.
Plant-based fiber that is durable, breathable, and absorbent. It has no natural elasticity, making the garment firm and durable.
Made from the stalks of the flax plant. Linen has probably been in use for more than 10,000 years. The fiber has higher tensile strength than cotton, absorbs more moisture and dries faster — which is why it feels cooler. In our experience it softens with use and washing.
Produced from the cocoon of the silkworm. The fiber is counted among the most exclusive textile fibers, both for its luster and its strength. It absorbs up to a third of its own weight in moisture without feeling wet, and can feel cool against the skin.
Viscose chemically regenerated from bamboo pulp — a manufactured fiber, not a natural one, despite what the name suggests. It has a fantastic drape, is silky soft, cooling and moisture-absorbent. US labeling rules require it be called viscose or rayon made from bamboo, not simply bamboo.
A synthetic fiber that is extremely durable and elastic. Almost always blended with wool (especially in sock yarn) to add strength.
An inexpensive and machine-washable synthetic fiber that mimics wool. It is non-itchy and colorfast, but lacks breathability and pills easily.
Rarely used alone in knitting yarn, but often appears as a small share in blends — as an effect thread, as the load-bearing core of thick yarns, or as filling in tape yarns. It is hard-wearing and holds its shape, but does not move moisture away from the skin the way wool does.
See the full overview of popular yarn brands in the US and UK for more examples, yardage and gauge per weight category.
Even though each fiber has its own care recommendations (see the cards above), a few general rules apply to all hand-knitted items. Always check the ball band before washing – it states the exact temperature and washing method the manufacturer recommends, and the details can vary even within the same fiber type depending on how it was processed.
Superwash-treated yarn (commonly seen with Merino wool) is the exception to the hand-wash rule: it usually withstands machine washing on a wool cycle because the fiber surface has been treated to prevent felting. Keep in mind that the treatment can make the yarn slightly slicker to knit with and reduce its natural elasticity somewhat.
Wool can itch depending on the fiber's micron count (thickness). Thicker fibers itch more because they poke the skin, while fine fibers like Merino wool bend and feel soft. Some people are also sensitive to lanolin, the natural fat in wool.
Superwash is wool that has been chemically treated or coated with a thin polymer to prevent the fibers from felting. This allows the yarn to be machine-washed without shrinking, but it loses some of its natural breathability and odor resistance.
It is possible, but remember that cotton and wool behave very differently. Cotton lacks elasticity, so a cotton garment will easily sag and lose its shape if the pattern was designed for wool. Cotton also breathes differently and doesn't warm when wet.
Blend yarns combine multiple fiber types to utilize the best of both worlds. For example, a blend of wool and nylon provides a yarn that is warm but also highly durable (perfect for socks). Silk and mohair are often blended to provide luster and strength to the fuzzy mohair.
Micron ranges and fiber classifications follow The Woolmark Company for wool, and Textile Exchange for fiber production and certification. Fineness is a range, not a fixed number: the same breed varies by flock and by which part of the fleece the fiber came from.