Yarn Glossary
Yarn Weights
Lace
CYC 0 · 400+ m/50g · 1.5–2.5mmThe finest yarn with 400+ m/50g, delicate and almost see-through. Perfect for intricate shawls and lace patterns. Needles 1.5–2.5mm, CYC 0.
Fingering / Sock Weight
CYC 1 · 350–400 m/50g · 2–3mmFine all-round yarn, classic for socks (350–400 m/50g). Tough enough for everyday wear, fine enough for elegant shawls.
Sport
CYC 2 · 250–350 m/50g · 3–3.75mmBetween sock yarn and DK, around 250–350 m/50g. Great for lightweight sweaters, baby items, and accessories that don't add bulk.
DK / Double Knitting / Light
CYC 3 · 200–250 m/50g · 3.75–4.5mmThe most versatile yarn weight (200–250 m/50g, needles 3.75–4.5mm). Sweaters, hats, scarves, suitable for almost everything.
Worsted / Aran / Medium
CYC 4 · 120–200 m/50g · 4.5–5.5mmClassic for winter sweaters and blankets (120–200 m/50g, needles 4.5–5.5mm). Cable patterns look especially bold in this weight.
Bulky / Chunky
CYC 5 · 60–120 m/50g · 5.5–8mmThick yarn for quick projects (60–120 m/50g, needles 5.5–8mm). Cosy hats, chunky scarves, and home accessories.
Super Bulky / Super Chunky
CYC 6 · 40–60 m/50g · 8–12mmExtra thick yarn at 40–60 m/50g, needles 8–12mm. Voluminous scarves and home accessories, ideal for arm knitting.
Jumbo
CYC 7 · < 40 m/50g · 12mm+The thickest yarn there is (< 40 m/50g, needles 12mm+). Giant cosy blankets and statement scarves, often knitted with your arms.
Technical Terms
Run Length
The number of metres per 50g (or 100g). More informative than skein weight when comparing and substituting yarns.
Yarn Weight
The thickness of yarn, divided into 8 CYC categories from Lace (0) to Jumbo (7). Determines needle size and run length.
Needle Size
The recommended size in mm, a guideline, not a rule. Your personal tension and gauge swatch decide the right needle.
Gauge
A 10×10 cm test swatch before your project. Count stitches and rows, then adjust needle size, so the finished piece fits.
Garter Stitch (Krausrechts)
Every row is knitted. This creates a firm, ridged fabric that looks the same on both sides and lies flat without curling.
Fiber Composition
What is your yarn made of? Wool, cotton, acrylic? The fibres determine warmth, care requirements, stretch, and how well yarns substitute each other.
Animal-free (Vegan)
Yarns with no animal fibres, no wool, silk, or alpaca. Plant-based (cotton, linen, bamboo) or synthetic (acrylic, polyester) alternatives.
Similarity Score
Shows how well a yarn works as a substitute, calculated from fibre composition, gauge, and run length. Above 80% is a solid swap.
Arm Knitting
Knitting with your arms instead of needles, for Super Bulky and Jumbo yarns (CYC 6–7). Chunky, voluminous blankets and scarves in record time.
Craft Yarn Council (CYC)
The US trade body that classifies yarn into 8 categories from Lace (0) to Jumbo (7). Makes it easy to compare yarns from different brands and countries.
Sustainability Certifications
These labels appear on yarns and textiles. They indicate that a product meets specific environmental or social standards.
GOTS – Global Organic Textile Standard
One of the world's most rigorous organic certifications. It covers organically grown natural fibres and prohibits harmful chemicals throughout the entire supply chain — from field to finished yarn.
OEKO-TEX Standard 100
Tests textiles for over 100 harmful substances. Yarn bearing this label is considered safe for health — even if the fibres were not organically grown.
OEKO-TEX Standard 100 Class 1
The strictest class of OEKO-TEX Standard 100, designed for products that come into contact with infant skin. Limits for harmful substances are particularly low.
Mulesing-Free
Confirms that sheep have not been subjected to mulesing — a painful procedure common with Australian Merino wool. Relevant for anyone who cares about animal welfare.
RWS – Responsible Wool Standard
Certifies species-appropriate sheep farming and sustainable land management. The certification covers animal welfare, soil health, and social responsibility across the entire farm.
RAS – Responsible Alpaca Standard
Similar to RWS but specifically for alpacas. Ensures that animals are kept in a species-appropriate manner and land is managed sustainably.
Fairtrade
Guarantees fair wages and safe working conditions for farmers and producers in developing countries. Supports local communities through minimum prices and premiums.
IVN BEST
Germany's strictest organic certification for natural textiles, issued by the International Association of Natural Textile Industry. Goes beyond GOTS in several areas, e.g. dyes and auxiliaries.
Bluesign
Certifies environmentally responsible manufacturing processes with a particular focus on chemical management, water consumption, and safe working conditions in textile factories.