The Edit — Craft
Crochet Hook Sizes: Letters, Millimetres and Yarn
A crochet hook can carry a US letter, a number and millimetres, and only the millimetres mean the same from brand to brand. The Craft Yarn Council's chart, the hook for each yarn, and why steel hooks count backwards.
This guide is research-led: we have not handled these units ourselves. If you buy through our links we may earn a commission — it never changes a pick.Research-led, nothing handled. We may earn from links; it never changes a pick. How we choose
This page reads the Craft Yarn Council’s hook size chart and its yarn weight system, and the 6 hook sets after it are ranked by how Amazon shoppers rate them, as How we choose describes. Nothing here was handled or tested.
Best for Fine to bulky
Watch for Letters off the chart
Best for A first set
Watch for Stops at 6 mm
Best for Every size in a case
Watch for No steel hooks
Best for Replacing old hooks
Watch for Sizes not listed
Best for Bulky yarn
Watch for Nothing under 6.5 mm
Best for Thread and lace
Watch for Not for yarn
The millimetre size is the one that means the same everywhere
The Craft Yarn Council, the US yarn trade body, says letter and number sizes vary from company to company, and tells crocheters to rely on the millimetre size on the package. That is the size to buy by and the size to read in a pattern. A letter is a convenience. Its regular hook chart runs from 2.25 mm (B-1) to 30 mm (T/X).
| Millimetres | US size |
|---|---|
| 2.25 mm | B-1 |
| 2.75 mm | C-2 |
| 3.25 mm | D-3 |
| 3.5 mm | E-4 |
| 3.75 mm | F-5 |
| 4 mm | G-6 |
| 5 mm | H-8 |
| 5.5 mm | 9 |
| 6 mm | J-10 |
| 6.5 mm | K-10½ |
| 8 mm | L-11 |
| 9 mm | M/N-13 |
| 10 mm | N/P-15 |
| 15 mm | P/Q |
Brands label the same hook with different letters
The Yarniss 14-size set shows the council’s point on its own label. It calls its 2 mm hook a B, where the council’s B-1 is 2.25 mm, and its 10 mm hook an N, where the council lists 10 mm as N/P-15. Neither is wrong: the letters were never fixed. The set runs from 2 to 10 mm in 14 sizes, with 9 yarn needles, 10 stitch markers, scissors and a case.
Yarniss 14-Size Ergonomic Crochet Hooks, 2 to 10 mm
14 ergonomic hooks from 2 to 10 mm, with 9 yarn needles, 10 markers, scissors and a case.
Current price shown on Amazon. We may earn a commission.
| Sizes | 14, 2 mm (B) to 10 mm (N) |
|---|---|
| Extras | 9 needles, 10 markers |
| Handle | Ergonomic grip |
14 sizes from fine to bulky, for a crocheter who reads the millimetres.
Buy it if
- Fine to bulky yarn from one case
Don't buy it if
- Its letters differ from the council's chart
Match the hook to the number on the yarn label
Every yarn label carries a weight number from 0 to 7, and the council recommends a hook range for each. Start in the middle of the range, then adjust to the pattern’s gauge. The yarn weight guide explains the label in full.
| Yarn weight | Types of yarn | Hook, mm | Hook, US |
|---|---|---|---|
| 1 | Sock, fingering, baby | 2.25–3.5 mm | B-1 to E-4 |
| 2 | Sport, baby | 3.5–4.5 mm | E-4 to 7 |
| 3 | DK, light worsted | 4.5–5.5 mm | 7 to 9 |
| 4 | Worsted, afghan, aran | 5.5–6.5 mm | 9 to K-10½ |
| 5 | Chunky, craft, rug | 6.5–9 mm | K-10½ to M-13 |
| 6 | Roving | 9–15 mm | M-13 to Q |
| 7 | Jumbo, roving | 15 mm and up | Q and up |
Tulip’s Etimo Rose covers the sizes a beginner reaches for
DK and worsted yarns, weights 3 and 4, take hooks from 4.5 to 6.5 mm. The Tulip Etimo Rose set has 9 soft-grip hooks from 2 to 6 mm, every half millimetre, in a pink case with a tassel. That covers yarn weights 1 to 3 and the bottom of weight 4. Above 6 mm, add a bulky hook.
Tulip Etimo Rose Crochet Hook Set
9 soft-grip hooks from 2 to 6 mm in half-millimetre steps, in a pink case.
Current price shown on Amazon. We may earn a commission.
| Sizes | 2–6 mm, every 0.5 mm |
|---|---|
| Hooks | 9 |
| Case | Pink, with a tassel |
9 sizes in half-millimetre steps, as a first set or a gift.
Buy it if
- A gift for a new crocheter
Don't buy it if
- Bulky yarn: tops out at 6 mm
Katech puts 21 hooks and the extras in one case
The Katech 85-piece set holds 2 runs of hooks: 9 soft-grip hooks from 2.0 to 6.0 mm and 12 aluminium hooks from 2.0 to 8.0 mm. Each is marked with its size and colour-coded. The rest of the 85 pieces are ring and locking stitch markers and yarn and sewing needles. Katech’s listing names no steel lace hooks.
Katech Crochet Hooks Set with Case, 85 Pieces
9 soft-grip hooks from 2 to 6 mm and 12 aluminium hooks from 2 to 8 mm, with markers and needles.
Current price shown on Amazon. We may earn a commission.
| Soft-grip | 9, 2.0–6.0 mm |
|---|---|
| Aluminium | 12, 2.0–8.0 mm |
| Marking | Sizes marked, colour-coded |
2 full runs of hooks and the notions, for a crocheter who wants it all in one case.
Buy it if
- A beginner who wants every size in one case
Don't buy it if
- Steel lace hooks: none stated
The Clover Amour set is the soft-grip upgrade
The Clover Amour 10-hook set is 10 easy-grip hooks in a different bright colour for each size. Clover’s listing does not print the 10 sizes, so check the box image or the Clover site before buying for a pattern. The colours do the job a letter does at a glance.
Clover Amour Crochet Hook Set, 10 Sizes
10 Clover Amour hooks with easy-grip handles in bright colours.
Current price shown on Amazon. We may earn a commission.
| Hooks | 10 sizes |
|---|---|
| Handle | Easy grip |
| Sizes | Not listed on the listing |
10 colour-coded soft-grip hooks, to replace a drawer of mismatched ones.
Buy it if
- A crocheter replacing a mixed drawer of hooks
Don't buy it if
- Checking sizes before buying: not listed
Thick yarn needs hooks above 6.5 mm
Chunky and roving yarns, weights 5 and 6, take hooks from 6.5 to 15 mm. The Clover Amour thick-yarn set is 7 hooks at 6.5, 7, 8, 9, 10, 12 and 15 mm, with elastomer rubber handles, made in Japan. It starts where the Tulip set stops.
Clover Amour Crochet Hooks, Set of 7, for Thick Yarns
7 large hooks from 6.5 to 15 mm with rubber handles, colour-coded and made in Japan.
Current price shown on Amazon. We may earn a commission.
| Sizes | 6.5, 7, 8, 9, 10, 12, 15 mm |
|---|---|
| Handle | Elastomer rubber |
| Made in | Japan |
7 big hooks for chunky blankets and weight 6 yarn.
Buy it if
- Chunky blankets and weight 6 yarn
Don't buy it if
- Fine yarn: nothing under 6.5 mm
Steel hooks count backwards
Steel hooks are for crochet thread and lace weight yarn, and the council notes they are numbered the reverse way: the higher the number, the smaller the hook. The Clover Amour steel set states 7 sizes, from size 0 at 1.75 mm down to size 12 at 0.60 mm. Clover’s numbers differ from the council’s, which gives size 14 at 0.9 mm as the smallest; Clover’s 0.90 mm is its size 8. The millimetres settle it again.
Clover Amour Steel Crochet Hook Set
7 steel hooks from 0.60 to 1.75 mm, for crochet thread and lace, with rubber grips.
Current price shown on Amazon. We may earn a commission.
| Sizes | 0/1.75 mm to 12/0.60 mm |
|---|---|
| Hooks | 7 steel |
| Handle | Elastomer rubber |
7 steel hooks for thread, doilies and fine lace.
Buy it if
- Doilies, lace and thread work
Don't buy it if
- Yarn: these are for thread
Swatch first, whatever the label says
The council’s rule for every hook is the same: crochet a gauge swatch and compare it with the pattern. A swatch larger than the pattern’s gauge needs a smaller hook, and a smaller swatch needs a larger one. For a first project with the hook already chosen, the crochet kits guide compares 6 beginner boxes, and the knitting kits guide covers the other craft.
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