How to Read Yarn Labels — Complete Guide

A yarn label packs a surprising amount of information into a small space — and most of it genuinely matters for how your knitting will turn out. Once you know how to read one, you'll have a clear picture of what the yarn is, how to use it, how to care for it, and whether it'll work for your project. This guide goes through every element of a yarn label so nothing is left ambiguous.

Weight Category

The Craft Yarn Council (CYC) standardised yarn weight into 8 categories, numbered 0–7, running from ultra-fine to jumbo:

0 — Lace: Extremely fine. Thread-like. Used for delicate lace shawls. Recommended needle size 1.5–2.25mm.

1 — Super Fine (Fingering/Sock): Thin. Standard sock yarn. 2–2.75mm needles.

2 — Fine (Sport/Baby): Slightly heavier than fingering. 2.75–3.25mm needles.

3 — Light (DK/Light Worsted): The classic "double knitting" weight. 3.25–3.75mm needles.

4 — Medium (Worsted/Aran): The most widely used weight. 3.75–5mm needles.

5 — Bulky: Chunky knitting. 5–8mm needles.

6 — Super Bulky: Very thick. 8–12.75mm needles.

7 — Jumbo: The thickest category. Arm knitting territory. 12.75mm+ needles.

Note that weight categories are broad — two yarns both labelled "4 — Medium (Worsted)" can knit to quite different gauges. Always check the actual gauge recommendation alongside the weight category.

Fibre Content

Fibre content is listed in order of percentage, highest first. "80% Merino Wool, 20% Nylon" means the yarn is mostly merino with nylon added for strength. This matters for several reasons:

Care: Wool needs gentle washing; acrylic can go in the machine. The dominant fibre usually dictates care instructions.

Durability: Nylon adds strength — important for socks and elbows. Pure plant fibres can pill more easily.

Blocking: Protein fibres (wool, alpaca, silk) block well with water and steam. Plant fibres (cotton, linen) respond less dramatically to blocking. Acrylic needs steam to block and won't hold shape from water alone.

Allergies and sensitivities: Relevant if you're knitting for someone who reacts to wool or synthetic fibres.

Meterage vs Weight

The label will tell you both the weight of the ball (typically in grams) and the length of yarn in that ball (in metres and/or yards). For example: "100g / 400m".

Meterage is more useful than grams for substitution and yardage planning — it tells you how much yarn you actually have. A 100g ball of bulky acrylic might have 100m; a 100g ball of fingering-weight merino might have 400m. They weigh the same but behave completely differently.

When calculating how much yarn a project needs, always use the meterage figure from the pattern, not the ball count.

Recommended Needle Size

The needle size listed on the label is the manufacturer's suggestion for a standard gauge swatch. It's a starting point, not a rule. The designer of your pattern may use a different needle size — deliberately — to achieve a denser or more open fabric. Always follow the pattern's recommended needle size and adjust from there based on your own swatch.

If you tend to knit tightly, you may need to go up one needle size. If you knit loosely, you may need to go down one. The label needle size assumes an average tension.

Care Symbols

Care symbols follow a standardised international system. The main ones you need to know:

Tub with water: Washing. A tub with a hand = hand wash only. A plain tub = machine washable. A tub with lines underneath = machine wash on a gentle cycle. A number inside the tub = the maximum temperature in degrees Celsius.

Triangle: Bleaching. A plain triangle = bleach is OK. A crossed-out triangle = do not bleach. A triangle with two lines = only non-chlorine bleach.

Square with a circle inside: Tumble drying. A crossed-out version = do not tumble dry. Dots inside indicate heat level (one dot = low heat, two = medium, three = high).

Iron: Pressing/ironing. Dots indicate heat level. A crossed-out iron = do not iron.

Circle: Dry cleaning. A letter inside indicates the dry cleaning solvent type. A crossed-out circle = do not dry clean.

For most hand-knitting yarns — especially wool — look for the hand wash symbol. Superwash wool and most plant fibre/acrylic blends will show a machine wash symbol, usually with a low temperature and gentle cycle indicator.

Dye Lot

The dye lot number is one of the most important — and most ignored — pieces of information on a yarn label. Yarn is dyed in batches, and even with the same colour name and formula, two different dye lots can look different under certain lighting conditions. The difference is often subtle, but it becomes visible as a horizontal stripe if you switch lots mid-project.

Always buy all the yarn for a single project from the same dye lot. Check the lot number on every ball before buying — don't assume they'll all match. If you need to use a second lot, alternate balls every two rows to blend the transition gradually.

Some yarns (particularly hand-dyed indie yarns) are marked "no dye lot" — this means the colour is consistently reproducible, so dye lot matching doesn't apply.

WPI — Wraps Per Inch

WPI stands for wraps per inch and is a direct measurement of how thick a yarn is, bypassing weight category labels entirely. Wrap the yarn around a ruler or a WPI tool without overlapping and without stretching — count how many wraps fit in one inch.

35+ WPI = lace weight

18–22 WPI = fingering/sock weight

14–16 WPI = sport/baby weight

11–13 WPI = DK weight

9–10 WPI = worsted weight

6–8 WPI = bulky

Under 6 WPI = super bulky or jumbo

WPI is especially useful when substituting an unlabelled yarn (from a destash, inherited stash, or craft store oddment with the label missing) — it tells you exactly what weight category you're working with.

Country of Origin

The country where the yarn was produced. This is relevant if you're interested in supporting particular regional textile industries, if you have concerns about animal welfare standards, or if you want to verify claims about specific fleece origins. "Peruvian Alpaca" produced in China is a different product from Peruvian Alpaca sourced and processed in Peru — the label country of origin will tell you where processing happened, though it may not tell you where the fibre was sourced.

Have a mystery yarn with no label? Emma can help you identify it →