Know your yarn.
Lost the label? Measure it. Two numbers — wraps per inch, or stitches in a swatch — and you get the weight, the hook and needle range, and the yardage to expect.
Wrap around a pencil for one inch, snug, no gaps. Count the wraps.
From a swatch, a label, or the pattern you are matching.
Everything works from the same standard measurements
Weight from a measurement
Wraps per inch or stitches in a swatch — the category falls out of the number, no label needed.
Hooks across three systems
US letters, UK numbers and millimetres, with the yarn weights each size suits.
Gauge, recalculated
Your swatch does not match the pattern? Get the stitch count and the extra yarn it costs.
Substitution with skeins
Total the yardage, add a buffer, and get the number of skeins to actually buy.
Lace to jumbo, at a glance
Measure
Wrap the yarn around a pencil for one inch and count the wraps. No label needed.
Read the answer
The CYC category, the hook and needle range, and the yardage per 100 g.
Use it
Convert a hook, recalculate a pattern, or work out how many skeins to buy.
Why the label is not enough
Yarn weight is a category, not a measurement. Two yarns both sold as DK can differ by a full needle size, and a "worsted" from one brand can knit at the gauge another brand calls aran. The category tells you roughly where to start; the wraps per inch tells you what you actually have.
That is why this site asks for a number instead of a name. Every tool runs in your browser — nothing is uploaded, nothing is stored, and the page works with the network off once loaded.
Common questions
What are the yarn weights in order of thickness?
Lace (0), super fine (1), fine (2), light (3), medium (4), bulky (5), super bulky (6), jumbo (7) — the Craft Yarn Council categories, thinnest to thickest.
How do I know the weight of a yarn with no label?
Measure wraps per inch: wrap snugly around a pencil for one inch and count. 9–11 wraps is medium (worsted), 12–14 is light (DK), 15–18 is fine (sport), 19–22 is super fine (fingering).
Is 8-ply the same as DK?
Usually yes in UK and Australian terms. Ply counts are a spinning description, not a standard, so trust the gauge over the ply number.