Hook & yarn cheat sheet
Yarn weight symbols (0–7), suggested hook sizes in mm and US letters, and typical uses.
| CYC | Weight name | Also called | Hook (mm) | Hook (US) |
|---|---|---|---|---|
| 0 | Lace | Thread, cobweb | 1.5–2.25 mm | Steel 6–8 / B–1 |
| 1 | Super fine | Sock, fingering, baby | 2.25–3.5 mm | B–1 to E–4 |
| 2 | Fine | Sport, baby | 3.5–4.5 mm | E–4 to 7 |
| 3 | Light | DK, light worsted | 4.5–5.5 mm | 7 to I–9 |
| 4 | Medium | Worsted, aran | 5.5–6.5 mm | I–9 to K–10½ |
| 5 | Bulky | Chunky, craft | 6.5–9 mm | K–10½ to M–13 |
| 6 | Super bulky | Roving | 9–15 mm | M–13 to Q |
| 7 | Jumbo | Roving, arm crochet | 15 mm+ | Q and larger |
Stitch choice and tension change drape—your pattern schematic and yarn band override any generic chart.
US crochet hook ↔ mm
Nominal sizes; hooks can differ slightly by brand.
| mm | US |
|---|---|
| 2.25 | B-1 |
| 2.75 | C-2 |
| 3.25 | D-3 |
| 3.5 | E-4 |
| 3.75 | F-5 |
| 4 | G-6 |
| 4.25 | G |
| 4.5 | 7 |
| 5 | H-8 |
| 5.5 | I-9 |
| 6 | J-10 |
| 6.5 | K-10½ |
| 8 | L-11 |
| 9 | M/N-13 |
| 10 | N/P-15 |
| 12 | P/Q |
| 15 | Q |
| 16 | S |
| 19 | T/U |
Yarn labels use CYC weight symbols (0 lace through 7 jumbo) and suggest hook ranges. Designers also write hooks in millimeters or US letters (E-4, G-6, and so on). A single cheat sheet keeps those systems in one place while you substitute yarn or translate a pattern.
Use the yarn weight table for typical projects and starting hook sizes, then the US ↔ mm hook chart when a pattern lists only one notation.
How to use the hook and yarn charts
- Find your yarn’s CYC number (or common name like DK, worsted, bulky) in the weight table.
- Note the suggested hook range in mm and US letters—then swatch, because fiber and tension vary.
- If a pattern only lists a US letter or only mm, convert with the hook chart before you start.
- Check gauge with the gauge calculator after you pick a hook so finished sizes stay on track.
Choosing hooks and yarn
- Suggestions are starting points—always swatch for garments and fitted amigurumi.
- Going up a hook size loosens fabric; going down tightens it and can hide stuffing better in toys.
- When substituting yarn, match weight and fiber behavior (drape vs. structure), not only the label number.
Frequently asked questions
- What does yarn weight 4 mean?
- CYC 4 is medium / worsted-weight yarn—common for blankets, amigurumi, and many wearables. Exact yardage and feel still depend on the brand.
- Are US hook letters the same worldwide?
- US letter/number combos map to millimeter sizes, but older or non-US brands may differ slightly. Prefer mm when precision matters.
- Is this chart free?
- Yes. Browse it anytime without an account; pair it with free tutorials and other OpenCrochet tools.
Gauge calculator · US ↔ UK terms · Pattern grading · Free tutorials · All tools