Crochet hook size chart

Crochet hooks
mm	US	Yarn weights
2.25 mm	B-1
2.5 mm	–
2.75 mm	C-2
3.125 mm	D
3.25 mm	D-3
3.5 mm	E-4
3.75 mm	F-5
4 mm	G-6
4.25 mm	G
4.5 mm	7
5 mm	H-8
5.25 mm	I
5.5 mm	I-9
5.75 mm	J
6 mm	J-10
6.5 mm	K-10½
7 mm	–
8 mm	L-11
9 mm	M/N-13
10 mm	N/P-15
11.5 mm	P-16
12 mm	–
15 mm	P/Q
15.75 mm	Q
16 mm	Q
19 mm	S
25 mm	T/U/X
30 mm	T/X

Steel crochet hooks
mm	US	Yarn weights
3.5 mm	00
3.25 mm	0
2.75 mm	1
2.7 mm	00
2.55 mm	0
2.35 mm	1
2.25 mm	2
2.2 mm	2
2.1 mm	3
2 mm	4
1.9 mm	5
1.8 mm	6
1.75 mm	4/0
1.7 mm	5
1.65 mm	7
1.6 mm	6
1.5 mm	8/7/2
1.4 mm	9/8
1.3 mm	10
1.25 mm	9/4
1.15 mm	10
1.1 mm	11
1.05 mm	11
1 mm	12/6
0.95 mm	13
0.9 mm	14/8
0.85 mm	13
0.75 mm	14/10
0.6 mm	12

Knitting needles
mm	US	Yarn weights
1.5 mm	000
1.75 mm	00
2 mm	0
2.25 mm	1
2.75 mm	2
3 mm	–
3.125 mm	3
3.25 mm	3
3.5 mm	4
3.75 mm	5
4 mm	6
4.25 mm	6
4.5 mm	7
5 mm	8
5.25 mm	9
5.5 mm	9
5.75 mm	10
6 mm	10
6.5 mm	10½
7 mm	–
8 mm	11
9 mm	13
10 mm	15
12.5 mm	17
12.75 mm	17
15 mm	19
19 mm	35
25 mm	50
35 mm	70

Pick your hook by the millimeter size on its package, as the hint under the list says. The chart above gives that size’s US letter or number from the Craft Yarn Council (CYC), the yarn weights the hook suits and, where CYC lists one, the knitting needle of the same size.

Not sure which hook to use? Start with the one on your yarn label or pattern, then check it with a gauge swatch.

How to use the crochet hook size chart

Leave “Crochet hooks” selected, or switch to “Knitting needles”.
Choose your size from the list. Regular hooks show the mm with the letter, as in 5 mm (H-8). Steel hooks (the small hooks the Good to know box above describes) have their own group, by mm.
Read the result: the US size and the yarn weights for that hook. For a regular hook, it also gives the knitting needle of the same mm, where CYC lists one. A hook on the edge of two ranges lists both weights: 5.5 mm (I-9) suits 3 Light and 4 Medium.
Find the highlighted row in the full chart above this guide. The page address keeps your choice, so you can bookmark or share it.

CYC gives no US size for 2.5 mm, 7 mm or 12 mm hooks. The chart shows “–” for these; the list says “no US size” and the result says “no CYC US size”. Go by the mm.

Crochet hook sizes: go by the mm, not the letter

CYC says “letter and number sizing vary from company to company”. A letter on its own can mean two sizes even in CYC’s chart: G-6 is 4 mm and G is 4.25 mm, I is 5.25 mm and I-9 is 5.5 mm, J is 5.75 mm and J-10 is 6 mm. P turns up in three rows: N/P-15 (10 mm), P-16 (11.5 mm) and P/Q (15 mm). And 4.5 mm has no letter at all, only the number 7.

So when a pattern calls for a “G hook”, look for the mm beside it. If there’s none, your swatch settles it. CYC’s advice: “Regardless of the number, letter or millimeter sizing, always complete a gauge swatch and compare it to the pattern gauge information. If your swatch is larger than the pattern gauge, redo a swatch using a smaller hook or needle.” If it’s smaller, CYC says to redo it with a larger hook. The gauge calculator turns your swatch’s count into stitch counts for your project.

Even CYC’s pages differ: its hook chart prints 9 mm as M/N-13, and its yarn weight table prints M–13. For a UK pattern, go by its mm too.

When you buy hooks, pick ones marked in mm as well as letters, like a ten-hook set marked 2.25 mm (B) to 6 mm (J) ad .

Crochet hook sizes and yarn weight

The yarn weights come from CYC’s recommended hook range for each yarn category. They’re ranges, not limits: CYC labels them guidelines only.

The ranges meet at their ends, so a hook on the edge of two ranges suits both weights: 6.5 mm (K-10½) is for 4 Medium and 5 Bulky.

Working with worsted? CYC lists “Worsted, Afghan, Aran” under 4 Medium, and its hook range for 4 Medium runs from 5.5 to 6.5 mm (I-9 to K-10½).

Read the hook column of a yarn chart, not the needle one, because the same mm suits a lighter yarn in crochet (the Good to know box above gives the 5 mm example).

To find a yarn’s weight from the gauge and hook size on its label, use the yarn weight chart. CYC counts crochet gauge for categories 1 to 7 in single crochet (UK double crochet) over 4", and 0 Lace in double crochets (UK treble crochet), with a footnote: “Lace weight yarns are usually knitted or crocheted on larger needles and hooks to create lacy, openwork patterns. Accordingly, a gauge range is difficult to determine. Always follow the gauge stated in your pattern.”

Steel crochet hook sizes: why to go by the mm

Skip this part unless you work with thread or lace-weight yarn.

Steel hook numbers run backward, as the Good to know box above says, and they also repeat. In CYC’s steel hook table, 00 is both 3.5 mm and 2.7 mm. CYC prints a 0 on two rows, 3.25 mm and 2.55 mm, and “4/0” on the 1.75 mm row. Clover labels its 1.75 mm hook “Amour Steel Crochet Hook No. 0 (1.75mm)”, which matches that 4/0 row. So a “size 0” steel hook without its mm could be any of three sizes. If you buy steel hooks, choose ones marked in mm, like a steel crochet hook set marked in mm ad .

For yarn weights, CYC’s yarn table names steel hooks only for 0 Lace, as “1.6–1.4 mm” and as steel “6, 7, 8”. Those numbers also sit on other rows (7 at 1.65 mm, 6 at 1.8 mm), so the chart matches by mm: only the steel 1.6, 1.5 and 1.4 mm rows show 0 Lace (the regular 2.25 mm B-1 hook also suits 0 Lace). “None in the CYC chart” means the steel hook falls outside that lace range, not that it’s unusable.

FAQs

What size is an H crochet hook?

In CYC’s chart, 5 mm (H-8). Check the mm on the package, since letters vary by company.

What size is a G crochet hook?

4 mm (G-6) or 4.25 mm (G): CYC lists both, as “Crochet hook sizes: go by the mm, not the letter” above explains.

What size crochet hook should a beginner use?

Lion Brand, a yarn company, suggests starting with worsted (medium, category 4) yarn, which in general calls for an “I to K (5.5 to 6.5 mm) hook”. That matches CYC’s 4 Medium hook range (5.5–6.5 mm, I-9 to K-10½). Your label has the final say.