Run Length & Needle Size
Which yarn weight matches which run length?
| Run Length (m/100g) | CYC | Yarn Weight | Needle Size (mm) | Typical Uses |
|---|---|---|---|---|
| 400+ | 0 | Lace | 1.5–2.25 | Shawls, lace scarves, wraps |
| 350–400 | 1 | Fingering | 2.25–3.25 | Socks, fine accessories |
| 250–350 | 2 | Sport | 3.25–3.75 | Baby clothes, light sweaters |
| 200–250 | 3 | DK | 3.75–4.5 | Sweaters, hats, scarves |
| 120–200 | 4 | Worsted | 4.5–5.5 | Winter sweaters, beanies |
| 60–120 | 5 | Bulky / Aran | 5.5–8 | Blankets, chunky sweaters |
| 40–60 | 6 | Super Bulky | 8–12 | Cowls, chunky arm warmers |
| < 40 | 7 | Jumbo | 12+ | Arm knitting, giant blankets |
All values are guidelines, the yarn label is always the most reliable source.
The label is gone but the yarn is still there — now what? Run length is your best clue. Weigh out 50 g of yarn, measure the length in metres, and match it to the table. In most cases that's enough to identify the weight category reliably.
Run length is also the most important factor for yarn substitution: what matters isn't the weight label, but whether the metres per gram match. Two yarns with the same CYC number can still have different run lengths — meaning you'd need a different number of skeins.
The "Typical uses" column shows the most common applications for each weight — but knitting has no hard rules. A DK blanket or Jumbo socks? Both possible, as long as your swatch matches.
Looking for a substitute for a specific project?
→ Find a yarn substituteFrequently Asked Questions
How do I find the yarn weight when the label is missing?
Measure the run length: wind off the yarn and weigh 50 g, then measure the length in metres. Look up the result in the table, run length usually identifies the weight category reliably. You can also knit a quick swatch to double-check.
What is the difference between run length and skein weight?
Skein weight (50 g, 100 g) only tells you how heavy the skein is. Run length tells you how many metres are on it. Two 50 g skeins can have completely different run lengths, a Lace yarn might have 400 m while a Bulky yarn has only 60 m.
I have a yarn with 400 m/100 g, what weight is that?
400 m/100 g is 200 m/50 g, which puts it in the Fingering or Sport category (CYC 1–2). Try it on 2.5–3.5 mm needles and knit a swatch to confirm.
How much yarn do I need for a sweater?
It depends on yarn weight and size. As a rough guide: a DK-weight adult sweater in size M needs around 1,000–1,200 m (about 8–10 skeins of 50 g / 120 m each). Your pattern will give you the exact amount.