You find a beautiful skein at the back of the cupboard. You simply cannot remember where it came from. The ball band is long gone, and now you are standing with an unknown yarn you cannot identify.
It is a classic problem in the knitting world. The yardage is unknown, the fibre content is a pure guess, and even the colourway has disappeared. You cannot simply look up a pattern and check whether the yarn works.
Fortunately, you can get remarkably far with a systematic approach. You do not need to know the precise details to be able to use the yarn. You just need to know enough to place it in the right technical category.
Visual identification
Start by getting the yarn under a good, direct light source to observe the physical details.
Thickness and weight category
The weight category does not describe how much the individual skein physically weighs on a scale. It describes the thickness of the strand. The knitting industry uses a standardised scale from 0 (Lace, very fine yarn) to 7 (Jumbo), and this is the most critical piece of information you need to find.
The most reliable method is to knit a quick gauge swatch. Cast on a small square on the needles you think suit the thickness, and count your stitches per 10 cm. Compare the result against the official Craft Yarn Council (CYC) scale:
| CYC | Category | Stitches/10 cm | Suggested needles |
|---|---|---|---|
| 0 | Lace | 33-40 sts | 1.5-2.25 mm |
| 1 | Fingering | 27-32 sts | 2.25-3.25 mm |
| 2 | Sport | 23-26 sts | 3.25-3.75 mm |
| 3 | DK | 21-24 sts | 3.75-4.5 mm |
| 4 | Worsted / Aran | 16-20 sts | 4.5-5.5 mm |
| 5 | Bulky | 12-15 sts | 5.5-8 mm |
| 6 | Super Bulky | 7-11 sts | 8-12.75 mm |
| 7 | Jumbo | ≤6 sts | 12.75+ mm |
This table is a guide. CYC and WPI do not measure exactly the same thing, so categories can overlap. Gauge and a swatch should always determine the final choice.
If you want a quick estimate without reaching for your needles straight away, you can use the WPI method (Wraps Per Inch). Wrap the yarn loosely around a ruler and count how many wraps sit side by side within exactly one inch (2.54 cm).
The number of wraps indicates the category:
- 30+ wraps: Lace
- 20-30 wraps: Fingering
- 16-20 wraps: Sport
- 14-18 wraps: DK
- 11-15 wraps: Worsted
- 8-11 wraps: Bulky
- 5-8 wraps: Super Bulky
The WPI measurement becomes unreliable if you stretch the yarn as you wrap. Lay the yarn loosely against the ruler so the strand’s natural diameter is preserved.
See the full overview of yarn weights and categories in the Guide to yarn weights.
Colour structure
A yarn’s colour typically falls into one of three categories:
- Solid: One homogeneous colour throughout the strand. The obvious choice for prominent cables and precise texture patterns.
- Marled: Two or more shades spun together in the strand, producing a soft, speckled colour play. It tends to obscure very complex patterns.
- Multi-coloured: Distinct, shifting colour sequences that are either industrially printed or hand-dyed in sections.
Sheen and light reflection
Hold the strand up to the light to assess the surface:
- Matte: Typically classic wool, cotton or dry acrylic fibres.
- Slight sheen: Fine merino, alpaca or blends with a touch of silk.
- High sheen: Pure silk, viscose, bamboo or Tencel.
Halo (fibre bloom)
Halo describes the visible bloom of loose fibres standing out from the core of the strand. Look at the yarn’s profile against a light background:
- No halo: The strand is smooth and sharp. Typically a worsted-spun wool, cotton or mercerised yarn.
- Moderate halo: Woolen-spun wool or shorter, softer wool fibres.
- Pronounced halo: Mohair, brushed alpaca, angora or kid silk blends.
What you can feel
Take the strand between your fingers, roll it back and forth, and feel its mechanical structure.
Softness and skin comfort
Use the inside of your wrist or your cheek as a gauge for fibre fineness (micron count):
- Extremely soft: Superwash merino, cashmere or silk mohair. No prickle at all (typically under 20 micron).
- Soft: Standard merino, fine alpaca and soft wool blends.
- Medium: Everyday utility wool or cotton.
- Rustic: Heritage Nordic or Icelandic wool breeds (e.g. Lopi), which contain coarser outer guard hairs (over 30 micron).
Yarn construction and twist
Pull gently on the strand and separate the fibres at the cut end to count the individual plies twisted around each other:
- Singles (single ply): One single, lightly spun fibre strand. It is vulnerable to abrasion and can bias slightly in stockinette.
- 2-ply: Two strands twisted together. Very common in fine wool yarns and fingering weight.
- 3- to 4-ply: The classic, round worsted structure that provides good durability and stitch definition for textured knitting.
- Cable-plied: Strands that are first twisted together in pairs, then those pairs are twisted in the opposite direction around each other. Produces an extremely stable and durable strand.
Tests you can do at home
If you have a short length of yarn to spare, you can run two simple tests to determine the fibre content.
The burn test
Cut a yarn end of about 5 cm, hold it with tweezers, and carefully bring it into the flame of a tealight. Perform the test over a sink or a fireproof surface.
| Reaction in and after the flame | Remaining ash / residue | Fibre type |
|---|---|---|
| Smells strongly of burning hair. Burns slowly and often self-extinguishes. | Black, irregular ash that crumbles easily between the fingers. | Protein fibre (Wool, alpaca, silk, mohair) |
| Smells of burning paper or wood. The flame catches quickly and burns evenly. | Fine, light and greyish or white ash. | Cellulose fibre (Cotton, linen, viscose, bamboo) |
| Chemical smell of burning plastic. Melts and produces chemical fumes. | Often leaves a hard, black or dark melt bead. | Synthetic fibre (Acrylic, polyester, nylon) |
| Smells of paper, but the strand curls up in the heat. | A soft ash edge combined with small, hard spots. | Blended yarn (e.g. wool/acrylic or cotton/polyester) |
The burn test cannot reliably identify blended yarns, but it can help distinguish between protein, cellulose and synthetic fibres.
The felt test
Wet a short piece of yarn with lukewarm water, place it in the palm of your hand, and roll it vigorously against your other palm for about a minute.
- Result A: The fibres felt together completely into a firm, inseparable mass. The yarn most likely contains untreated animal fibre, often wool. This means it should be hand-washed and is suitable for felting.
- Result B: The strand simply gets wet, keeps its structure and slides apart without felting. The yarn may be superwash-treated wool, cotton, or a synthetic fibre such as acrylic.
How Nysta automates the process
Nysta is built to guide you through the same questions: weight category, construction, sheen and surface texture. You fill in the parameters you can observe.
The app then compares your observations against the technical profiles in our yarn database. If your data matches a known yarn, the system suggests a possible match. If we cannot find an exact match, the app creates a custom profile for your yarn so you can still use the leftover in the pattern finder.
We do not remove all uncertainty, but we make it possible to use a leftover skein you would otherwise leave sitting.
Frequently asked questions
How do I find out what my yarn is? Start by determining the weight category via a gauge swatch or WPI measurement. Then assess the fibre content with a burn test or felt test. Those two pieces of information together give you enough to use the yarn in a pattern.
What is WPI? WPI stands for Wraps Per Inch. You wrap the yarn loosely around a ruler and count how many wraps sit side by side within one inch (2.54 cm). The number tells you which weight category the yarn belongs to.
Can you identify fibre content at home? You can get far with two simple tests. The burn test distinguishes between protein, cellulose and synthetic fibres. The felt test reveals whether the yarn is untreated animal fibre or not. Blended yarns are harder to identify with certainty.
Can Nysta help identify unknown yarn? Yes. Nysta guides you through the same questions about weight category, construction and surface texture. If your observations match a known yarn, the app suggests a possible match. Otherwise, a custom profile is created so you can still use the yarn in the pattern finder.
Add your yarn, even the ones without a ball band, and we’ll find patterns that fit.
Sign up for launch, and we’ll let you know when the app goes live in summer 2026.