Needles for each yarn weight
| Yarn weight | Knitting (mm) | Knitting (US) | Crochet hook (mm) |
|---|---|---|---|
| 0 Lace | 1.5–2.25 | 000–1 | 1.6–2.25 (steel 6–8 for thread) |
| 1 Super fine (fingering, sock) | 2.25–3.25 | 1–3 | 2.25–3.5 |
| 2 Fine (sport) | 3.25–3.75 | 3–5 | 3.5–4.5 |
| 3 Light (DK, light worsted) | 3.75–4.5 | 5–7 | 4.5–5.5 |
| 4 Medium (worsted, aran) | 4.5–5.5 | 7–9 | 5.5–6.5 |
| 5 Bulky (chunky) | 5.5–8 | 9–11 | 6.5–9 |
| 6 Super bulky | 8–12.75 | 11–17 | 9–15 |
| 7 Jumbo | 12.75 and up | 17 and up | 15 and up |
How to read the chart
Millimeters measure the needle’s diameter and are the most reliable system: a 4 mm needle is 4 mm everywhere. US numbers are a separate scale that grows with the needle. Old UK sizes, still printed on vintage patterns and needles, run the other way: a UK 14 is thin and a UK 000 is thick.
Some sizes have no exact match. There is no US equivalent for 3 mm, 7 mm or 7.5 mm, and some brands label 2.5 mm as US 1½. Japanese needles use their own numbers (for example, Japanese 6 is 3.9 mm), so check the millimeter size printed on the packet.
If you can’t read the size on an old needle, a needle gauge (a card with measured holes) will tell you. Push the needle through the smallest hole it fits.
Once you know your needle and gauge, the hat size calculator turns it into a cast-on number, and the blanket yarn calculator estimates how many skeins a blanket needs.
Last checked October 2026 against the Craft Yarn Council standards. Found a mistake? Tell us and we’ll fix it.