Photo2PatternFree yarn weight calculator
Yarn weight calculator for a band or a bare skein
Four readings can place a skein in the Craft Yarn Council’s 8 categories — a knit gauge, a crochet gauge, a needle diameter and a wrap count — and this page matches each one separately and tells you when they point in different directions. The whole standard is laid out to print and keep, and a ball band’s length and weight become meters per 100 g so one yarn can replace another by the measure that actually matters. It is free, it needs no account, and it estimates no project.
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- 8 CYC categories
- 4 readings compared
- Yards, meters, grams, ounces
Four readings, in descending order of what they are worth
Fill in whichever you have. A labeled ball band usually gives the first three; an unlabeled skein from a destash gives only the fourth, and the fourth is the weakest.
Blank it out to leave this reading out of the verdict.
Always fewer than the knit figure for the same yarn.
The diameter, not the US number — those are not linear.
Wound round a ruler with the strands touching and neither stretched nor squeezed.
What each reading says on its own
| Reading | You entered | Points at |
|---|---|---|
| Knit gauge from the band | 18 sts to 4 in | 4 MediumStockinette, which is what the standard's knit column measures. |
| Crochet gauge from the band | 12 sts to 4 in | 3 Light or 4 MediumSingle crochets. Comparing these against the knit column is meaningless — they are different stitches. |
| Suggested needle diameter | 5 mm | 4 MediumA starting suggestion from the manufacturer rather than a measurement of the yarn. |
| Wraps per inch, read ±2 | 10 wraps, so 8 to 12 | 3 Light or 4 Medium or 5 BulkyWidened by two wraps in each direction, which is how far two people reading the same yarn routinely differ. |
All 4 usable readings land on category 4, which is as good as this identification gets. Cast on with the needle the band suggests and measure what you actually make — the category was never going to tell you that.
The Standard Yarn Weight System, all eight rows
Rows matching your readings are marked. Knit figures are stockinette and crochet figures are single crochets, with the one exception noted under the table — the two columns are not comparable and were never meant to be.
| # | Category | Sold as | Knit sts / 4 in | Needle | Crochet sts / 4 in | Hook | Wraps / in |
|---|---|---|---|---|---|---|---|
| 0* | Lace | Fingering, 10-count crochet thread | 33–40 | 1.5–2.25 mmUS 000 to 1 | 32–42 | 1.4–2.25 mmUS steel 6, 7, 8 / regular B-1 | 35 and up |
| 1 | Super Fine | Sock, Fingering, Baby | 27–32 | 2.25–3.25 mmUS 1 to 3 | 21–32 | 2.25–3.5 mmUS B-1 to E-4 | 19–22 |
| 2 | Fine | Sport, Baby | 23–26 | 3.25–3.75 mmUS 3 to 5 | 16–20 | 3.5–4.5 mmUS E-4 to 7 | 15–18 |
| 3 | Light | DK, Light Worsted | 21–24 | 3.75–4.5 mmUS 5 to 7 | 12–17 | 4.5–5.5 mmUS 7 to I-9 | 12–14 |
| 4 | Medium | Worsted, Afghan, Aran | 16–20 | 4.5–5.5 mmUS 7 to 9 | 11–14 | 5.5–6.5 mmUS I-9 to K-10 1/2 | 9–11 |
| 5 | Bulky | Chunky, Craft, Rug | 12–15 | 5.5–8 mmUS 9 to 11 | 8–11 | 6.5–9 mmUS K-10 1/2 to M-13 | 6–8 |
| 6 | Super Bulky | Super Bulky, Roving | 7–11 | 8–12.75 mmUS 11 to 17 | 7–9 | 9–15 mmUS M-13 to Q | 4–5 |
| 7 | Jumbo | Jumbo, Roving | 6 and fewer | 12.75 mm and largerUS 17 and larger | 6 and fewer | 15 mm and largerUS Q and larger | 1–3 |
* Category 0: The council's own row measures this category in double crochets, not single, and gives steel hook sizes of 1.6-1.4 mm alongside a 2.25 mm regular hook. Lace is normally worked to a looser gauge than the needle range suggests, then blocked open.
Wraps per inch is a handspinners' convention, not part of the Craft Yarn Council standard. Two people measuring the same yarn routinely differ by two wraps, so read a WPI figure as narrowing the answer to two neighboring categories rather than choosing one.
Putting one yarn in the place of another
Substitution is a length problem, never a weight problem. Two skeins of the same 100 g can hold wildly different amounts of yarn, and it is the amount that has to match.
What the swap costs you
Your skein by length, not by mass
- Meters per 100 g
- 192.0
- Yards per 100 g
- 210.0
- Yards per ounce
- 59.5
This is the number the standard does not carry. Nothing in the eight rows above says how much yarn is on a ball, which is why two yarns of the same category are not interchangeable by ball count.
Balls of yours to buy
7
The pattern wants 1,400 yd in total. At 210 yd a skein that is 7 skeins with 70 yd over, weighing 700 g altogether. Skeins are whole objects, so this figure is rounded up and is exact once rounded — there is no partial ball to buy.
And what it does to the size. A design meant to finish 40 in wide is 200.0 stitches at the original’s 20 to four inches. Worked at your yarn’s printed 18, those same stitches come to 44.4 in — a difference of 4.4 in, or 11.1%.
Both figures are manufacturers’ numbers off a printed band, produced by somebody else’s hands on somebody else’s needles, and neither is a measurement of your knitting. Treat the percentage as a shortlisting device: it says whether two yarns are close enough to be worth swatching, and nothing more.
How to work out what a skein of yarn actually is
Length per 100 g is the number a substitution stands or falls on.
Enter whichever readings the skein will give you
A labeled ball band usually offers three: a knit gauge over four inches, a crochet gauge over four inches and a suggested needle diameter in millimeters. An unlabeled skein out of a destash bag offers only the fourth — wind it round a ruler with the strands touching, neither stretched nor squeezed, and count the wraps in an inch. Leave any field empty and it drops out of the verdict entirely rather than being guessed at.
Read the readings separately before you read the verdict
Each one is listed with the categories it points at and a note on what it is actually evidence of. They are in order of authority for a reason: gauge is the yarn's measured behavior in fabric, a suggested needle is what the manufacturer thinks you should start with, and wraps per inch is a handspinners' convention that no standards body publishes and that two people reading the same yarn commonly disagree about by two wraps. Where they conflict, believe them in that order.
Turn the ball band into length per 100 g before substituting anything
Weight categories do not make two yarns interchangeable — the standard specifies gauge, needle and hook and is silent about how much yarn is on a ball, so two skeins of identical mass in the same category can hold very different lengths. Put your skein's length and weight in and the panel gives meters per 100 g, yards per 100 g and yards per ounce, then works out how many of your skeins replace the balls a pattern calls for. That count is rounded up and is exact once rounded, because there is no half ball to buy.
Technical specifications
| Standard reproduced | The Craft Yarn Council's Standard Yarn Weight System, categories 0 to 7, with the trade names, knit and crochet gauge ranges, needle and hook diameters in mm and the US sizes as printed |
|---|---|
| Ways to place a skein | Four, ranked: knit gauge, crochet gauge, suggested needle diameter, wraps per inch. Any subset works and empty fields are excluded rather than assumed |
| How a wrap count is matched | Widened by ±2 wraps before matching, per the source note on the 8 published bands, so a reading returns neighboring categories rather than one |
| A gap in those bands | 23 to 34 wraps per inch falls in no published band at all — they run to 22 and resume at 35. The tool says so instead of snapping to the nearest |
| Ranges that overlap by design | 23 and 24 knit stitches to 4 in sit in both category 2 and category 3, and every needle range shares its endpoints with the next, so boundary values belong to two rows |
| What the standard does not carry | Length per unit weight. No row specifies yards or meters per ball, which is why substitution here is done from your own band rather than from the category |
| Unit handling | Band length in yards or meters, ball weight in grams or ounces, converted at 0.9144 m per yard and 28.3495 g per ounce; results given as meters per 100 g, yards per 100 g and yards per ounce |
| Network requests while you work | None. The eight-row table ships inside the page and every conversion is done in the tab |
Frequently asked questions
The label says worsted but it knits at 22 stitches. Which is right?
Both, and the label is the less useful of the two. Trade names like worsted, aran and DK are marketing terms with no defined boundary, which is exactly why the Craft Yarn Council numbered the categories in the first place — the council files worsted, afghan and aran together under category 4 precisely because the words had stopped distinguishing anything. A yarn labeled worsted that knits at 22 stitches to four inches is behaving as category 2 or 3, and the fabric is the fact. Use the label to find the shelf in the shop and the gauge to decide what to make.
The ball band is gone. Can I still identify the yarn?
You can narrow it to two neighboring categories, which is usually enough to choose a needle, and no further without knitting. Wrap the yarn round a ruler and count, then read the result as a band rather than a point: this tool widens your figure by two wraps in each direction before matching, because that is roughly how far two people reading the same skein land apart. Weighing the ball and measuring a length off it gives you the other half of the answer — length per 100 g is the number that decides whether it will do the job, and unlike the category it is a measurement rather than a classification.
Is wraps per inch trustworthy at all?
It is a real technique with a real weakness, and the weakness is the phrase everyone skips. Wrapping without stretching or crowding is the entire method, and neither condition can be checked afterwards — a slightly firm hand adds wraps, a lazy one loses them, and a lofty woollen-spun single compresses under tension in a way a tightly plied cotton does not, so the same nominal thickness reads differently. It is at its best on the yarn it was invented for, which is handspun with no band at all, and at its worst on anything fuzzy or elastic. Take it as a shortlist and settle it with a swatch.
Why do the knit and crochet gauge columns disagree so much?
Because they are counting different stitches, not the same yarn twice. The knit column measures stockinette; the crochet column measures single crochets, which are taller and consume more yarn per stitch, so far fewer of them fit in four inches — category 4 runs 16 to 20 knit stitches and 11 to 14 crochet stitches. Comparing them directly is meaningless. There is also a footnote worth knowing: the council's own category 0 row switches to double crochets rather than single ones, and gives steel hook sizes alongside the regular hook, so that row is not like the seven below it and is reproduced here as it is printed rather than tidied up.
Can I hold two strands of a thinner yarn to make a thicker one?
Yes, and it is one of the most useful tricks in a stash, but the result is not predictable from the categories. Doubling roughly doubles cross-sectional area, so two strands come out somewhere near a yarn one or two categories up — two fingering strands land around sport or DK, two DK around aran — and where exactly depends on how the plies sit together, which the numbers cannot tell you. Held yarn also behaves differently from a single yarn of the same thickness: it is loftier, it splits more readily on the needle, and it drapes less. Swatch the doubled strand and read the swatch, not the sum.
Does a category mean the same thing outside the United States?
The numbers do, because they are the council's and travel with the symbol printed inside the skein icon; the words around them do not. British patterns say double knitting and aran where American ones say DK and worsted, and Australian and New Zealand yarns are still often sold by ply — 4 ply, 8 ply, 12 ply — which counts the strands twisted together rather than the thickness, so an 8 ply is only reliably a DK because that is how the trade uses it. The trade names in the table here are the ones the council files under each number, and the gauge column is what actually crosses borders.
My skein reads 25 wraps and the tool says no category covers it. Is that a bug?
No, it is the published bands being honest. The wraps-per-inch bands in circulation run 19 to 22 for the finest normal yarn and then jump straight to 35 and up for lace, leaving everything between 23 and 34 wraps in no category at all. That gap is not an oversight this page should paper over: the bands were assembled by handspinners for the yarns they actually spin, not designed as a partition of all possible yarn, and a reading in the gap most often means a fine single or a crochet thread that the eight-category system was never built to place. Weigh it and measure a length instead — grist will tell you more about it than a category would.
About the eight categories, and what a category cannot tell you
The Standard Yarn Weight System was published to solve a naming problem. Before it, thickness was described by trade words that meant different things in different mills and different countries — worsted, aran, double knitting, 8 ply — and a pattern written in one vocabulary could not be safely bought in another. The council’s answer was to number eight bands and define each by what the yarn does rather than by what it is called, printing a gauge range, a needle range and a hook range for every one. That is genuinely useful and it is also the limit of what the system claims. A band is a range, so two skeins can be correctly labeled the same number and behave four stitches apart over four inches, and the number never promised otherwise.
What the standard leaves out entirely is the number a substitution actually turns on. There is no column for length per ball, because that is a decision each spinner makes about how to package the yarn, not a property of the yarn itself. Two skeins of the same category and the same 100 g can hold very different amounts, so replacing eight balls of one with eight balls of another is a coin toss. The arithmetic that works is length in, length out, and it is the only substitution arithmetic on this page. The gauge comparison beside it deliberately stops short of resizing anything: both band gauges are manufacturers’ figures produced by somebody else’s hands, so the percentage it prints is a shortlisting device, and the real number comes from a swatch you measured yourself.
Wraps per inch sits in the same file as the standard here but is not part of it, and the distinction matters enough to be printed under the table. Nobody publishes the wrap bands; they circulate among handspinners because they solve a real problem — a skein with no band at all — and they carry the accuracy that comes with a technique whose central instruction is not to pull too hard. This site takes the same line with every table it reproduces: the eight rows above are the council’s and are exact, the wrap bands are convention and are labeled as such, in the same way that the fixed palettes elsewhere here distinguish a color somebody specified from a color somebody measured. A LEGO mosaic is the opposite extreme and a useful thing to hold in mind: a 1x1 plate in a named color is the same object every time, so the bill of materials is a list. Yarn is a range wearing a number. If you are about to carry two colors through a piece rather than substitute one, tapestry crochet is where that gets charted.
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Your ball band stays on your desk
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