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Knitting Needle and Crochet Hook Size Charts
Search metric, US, old UK and Japanese knitting needle and crochet hook sizes, including steel hooks and labelled source differences.
Knitting Needle and Crochet Hook Size Charts: Matches exact metric diameters across published tables. CYC supplies US designations, Purple Kitty supplies old UK and Canadian conversions (UK only for steel), and Clover supplies Japanese manufacturer conventions. One US designation can have several diameters; these alternatives are retained. Runs 100% locally in your browser with zero server file uploads.
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US sizes are not uniform across makers for some sizes. Use the millimetre marking on the package. Japanese sizes below follow Clover's manufacturer convention; nearby diameters are not treated as equal.
43 matching diameters. A dash means no designation in the cited chart. An asterisk marks a variable US label or a difference between sources.
| Metric mm | US | Old UK / Canadian | Japanese 棒針 号 |
|---|---|---|---|
| 1.5 | 000 | — | — |
| 1.75 | 00 | — | — |
| 2 | 0 | 14 | — |
| 2.1 | — | — | 0 |
| 2.25 | 1 | 13 | — |
| 2.4 | — | — | 1 |
| 2.7 | — | — | 2 |
| 2.75 | 2 | 12 | — |
| 3 | — | 11 | 3 |
| 3.125 | 3 * | — | — |
| 3.25 | 3 * | 10 | — |
| 3.3 | — | — | 4 |
| 3.5 | 4 | — | — |
| 3.6 | — | — | 5 |
| 3.75 | 5 | 9 | — |
| 3.9 | — | — | 6 |
| 4 | 6 * | 8 | — |
| 4.2 | — | — | 7 |
| 4.25 | 6 * | — | — |
| 4.5 | 7 | 7 | 8 |
| 4.8 | — | — | 9 |
| 5 | 8 | 6 | — |
| 5.1 | — | — | 10 |
| 5.25 | 9 * | — | — |
| 5.4 | — | — | 11 |
| 5.5 | 9 * | 5 | — |
| 5.7 | — | — | 12 |
| 5.75 | 10 * | — | — |
| 6 | 10 * | 4 | 13 |
| 6.3 | — | — | 14 |
| 6.5 | 10.5 | 3 | — |
| 6.6 | — | — | 15 |
| 7 | — | 2 | — |
| 7.5 | — | 1 | — |
| 8 | 11 | 0 | — |
| 9 | 13 | 00 | — |
| 10 | 15 | 000 | — |
| 12.5 | 17 * | — | — |
| 12.75 | 17 * | — | — |
| 15 | 19 * | — | — |
| 19 | 35 | — | — |
| 25 | 50 | — | — |
| 35 | 70 | — | — |
Source differences: Purple Kitty gives knitting US 17 as 12 mm and US 19 as 16 mm; CYC gives 12.5–12.75 mm and 15 mm. Purple Kitty gives crochet P/16 as 16 mm; CYC gives P-16 as 11.5 mm. CYC also supplies crochet 7 at 4.5 mm and extra letter alternatives at 9 and 10 mm. The US column follows CYC throughout.
Sources and table dates
Accessed 2026-10-04.
Craft Yarn Council: knitting needles and regular hooks. https://www.craftyarncouncil.com/standards/hooks-and-needles
Craft Yarn Council: steel hooks. https://www.craftyarncouncil.com/standards/steel-crochet-hook-crochet-thread-sizes
Clover 2026 chart, page 1: knitting needles; page 2: regular and lace hooks. Manufacturer convention. https://www.clover.co.jp/recipe/takumikikakus.pdf
Purple Kitty: old UK / Canadian knitting and regular crochet conversions; old UK steel conversions (PDF page 1).
https://www.purplekittyyarns.com/info/knitting-needle-conversion.html
https://purplekittyyarns.com/info/crochet-hook-conversion.html
https://purplekittyyarns.com/info/steel-crochet-hook-conversion.pdf
CYC conversion tables
Craft Yarn Council, Hooks & Needles (knitting and regular hooks): https://www.craftyarncouncil.com/standards/hooks-and-needles . Steel Crochet Hook & Crochet Thread Sizes: https://www.craftyarncouncil.com/standards/steel-crochet-hook-crochet-thread-sizes Accessed 2026-10-04.
Japanese manufacturer convention
Clover 2026 specification chart: PDF page 1, knitting needles 0–15; page 2, regular hooks 2/0–10/0 and lace hooks 0–14. Manufacturer convention, not a claim of JIS certification. https://www.clover.co.jp/recipe/takumikikakus.pdf Accessed 2026-10-04.
Old UK and Canadian guides
Purple Kitty knitting: https://www.purplekittyyarns.com/info/knitting-needle-conversion.html ; regular crochet: https://purplekittyyarns.com/info/crochet-hook-conversion.html ; UK steel, PDF page 1: https://purplekittyyarns.com/info/steel-crochet-hook-conversion.pdf Accessed 2026-10-04.
Source differences
The US column follows CYC. Purple Kitty instead gives knitting US 17 as 12 mm and US 19 as 16 mm, and regular crochet P/16 as 16 mm. CYC gives knitting 17 at 12.5 and 12.75 mm, 19 at 15 mm, and crochet P-16 at 11.5 mm. Its crochet table also adds a 7 at 4.5 mm and letter alternatives at 9 and 10 mm. Accessed 2026-10-04.
How to use it
- Choose knitting needles, regular crochet hooks or steel hooks.
- Enter a size and optionally restrict the search to one numbering system.
- Read matching diameters and check the source notes before choosing a tool.
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Frequently asked questions
Why are some US numbers repeated at different diameters?
CYC records manufacturer variation. The internal index stores each designation once with all its documented diameters; the metric table shows each matching row.
Is Japanese size 8 the same as US 8?
No. Clover knitting size 8 is 4.5 mm; CYC US knitting size 8 is 5 mm. Japanese knitting, crochet and lace-hook numbers are separate.
Why are there blank cells?
A dash means the cited source supplies no designation at that exact diameter. Nearby values are not rounded into an equivalence.
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