Hooks

Crochet hooks and size conversion chart: US, metric (mm), UK and yarn weight

A crochet hook's size is the diameter of its shaft in millimetres. US letters, UK numbers and Japanese sizes are labels for those millimetres, and brands do not always agree on them. Convert any size below, find the hook for your yarn and project, then compare head styles, materials and handles.

hook sizes charted: 23
hook guides: 4

Tools

Crochet hook size converter and project recommender

Full hook size converter

Hook size converter

Pick a size in any system to see it in all the others.

Hook size

5 mm

US: H-8
UK: 6
Japanese: 8/0
Inches: 0.197

Yarn weight 4 Medium

Which hook for my yarn and project?

A starting hook to swatch with, from the Craft Yarn Council range for your yarn.

5.5 mm (US I-9)

Swatch with 5 mm (US H-8) and 6 mm (US J-10) too.

Even stitches at the gauge on the yarn label. Craft Yarn Council range for this yarn: 5.5–6.5 mm.

A starting point only. Tension and yarn vary, so check a 4 in (10 cm) swatch before a fitted project.

Swatch too big or small? Hook adjustment advisor

Size charts

Crochet hook size and conversion charts

Millimetres are the true size. Letters and numbers are labels, so check the mm on your hook and your pattern.

Standard crochet hook conversion chart (2 mm to 25 mm)

Crochet hook sizes in millimetres with US, UK and Japanese sizes and yarn weights
Metric	US	UK / Canada	Japanese	Yarn weight	Note
2 mm	–	14	2/0	0 Lace, 1 Super Fine	Sometimes labelled A or 0 in vintage sets.
2.25 mm	B-1	13	3/0	1 Super Fine
2.5 mm	–	12	4/0	1 Super Fine, 2 Fine	Metric size common in European and Japanese brands.
2.75 mm	C-2	11	–	1 Super Fine, 2 Fine	Check brandSome Boye C-2 hooks are 2.5 mm.
3 mm	–	11 or 10	5/0	2 Fine	No official US letter.
3.25 mm	D-3	10	–	2 Fine	Check brandSome Boye D-3 hooks are 3.125 mm.
3.5 mm	E-4	9	6/0	2 Fine, 3 Light
3.75 mm	F-5	9	–	3 Light
4 mm	G-6	8	7/0	3 Light, 4 Medium	Check brandBoye labels its 4.25 mm hook G-6; Susan Bates and Clover G-6 is 4 mm.
4.25 mm	G (Boye)	–	–	3 Light, 4 Medium	Check brandBoye's G-6. Not a Craft Yarn Council size.
4.5 mm	7	7	7.5/0	3 Light, 4 Medium	Number only, no letter. Not the same as a size 7 steel hook (1.65 mm).
5 mm	H-8	6	8/0	4 Medium
5.25 mm	I (Boye)	–	–	4 Medium	Check brandBoye's I-9. Craft Yarn Council I-9 is 5.5 mm.
5.5 mm	I-9	5	9/0	4 Medium
5.75 mm	J (Boye)	–	–	4 Medium	Check brandSome Boye J-10 hooks are 5.75 mm.
6 mm	J-10	4	10/0	4 Medium, 5 Bulky
6.5 mm	K-10½	3	–	5 Bulky
7 mm	–	2	7 mm	5 Bulky	Check brandMetric only; some brands stamp K or L.
8 mm	L-11	0	8 mm	5 Bulky, 6 Super Bulky
9 mm	M/N-13	00	9 mm	6 Super Bulky	Check brandBrands stamp it M-13 or N-13.
10 mm	N/P-15	000	10 mm	6 Super Bulky	Check brandBrands stamp it N-15 or P-15.
11.5 mm	P-16	–	–	6 Super Bulky, 7 Jumbo	Check brandBrand sizes vary between 11.5 and 12 mm.
15 mm	P/Q	–	–	6 Super Bulky, 7 Jumbo	Check brandBoye Q is 15.75 mm; Susan Bates Q is 16 mm.
16 mm	Q	–	–	7 Jumbo
19 mm	S	–	–	7 Jumbo	For roving and jumbo chenille.
25 mm	U	–	–	7 Jumbo

Brand sizing differences

Not every brand stamps the same letter on the same millimetres. These are the sizes in our chart where makers disagree, so follow the mm in your pattern and check your gauge.

2.75 mm (C-2)Some Boye C-2 hooks are 2.5 mm.
3.25 mm (D-3)Some Boye D-3 hooks are 3.125 mm.
4 mm (G-6)Boye labels its 4.25 mm hook G-6; Susan Bates and Clover G-6 is 4 mm.
4.25 mm (G (Boye))Boye's G-6. Not a Craft Yarn Council size.
5.25 mm (I (Boye))Boye's I-9. Craft Yarn Council I-9 is 5.5 mm.
5.75 mm (J (Boye))Some Boye J-10 hooks are 5.75 mm.
7 mm Metric only; some brands stamp K or L.
9 mm (M/N-13)Brands stamp it M-13 or N-13.
10 mm (N/P-15)Brands stamp it N-15 or P-15.
11.5 mm (P-16)Brand sizes vary between 11.5 and 12 mm.
15 mm (P/Q)Boye Q is 15.75 mm; Susan Bates Q is 16 mm.

Japanese crochet hook sizes

Japanese crochet hook sizes with metric and US equivalents
Japanese	Metric	US
2/0	2 mm	–
3/0	2.25 mm	B-1
4/0	2.5 mm	–
5/0	3 mm	–
6/0	3.5 mm	E-4
7/0	4 mm	G-6
7.5/0	4.5 mm	7
8/0	5 mm	H-8
9/0	5.5 mm	I-9
10/0	6 mm	J-10

Above 10/0, Japanese hooks are labelled in millimetres.

Steel crochet hook sizes for thread and lace

Steel numbers run backwards: size 14 is the finest. Diameters vary by brand, so each size is a range. A steel size 10 is not a US J-10.

US steel crochet hook sizes with metric range, UK size and thread
US steel	Metric	UK	Crochet thread
00	3.5 mm	–	Pearl cotton 3, doubled bedspread cotton
0	2.7–3.25 mm	–	Size 3 thread
1	2.25–2.75 mm	1	Size 3 to 5 thread
2	2.1–2.25 mm	1.5	Size 5 thread
3	2–2.1 mm	2	Size 5 to 10 thread
4	1.75–2 mm	2.5	Size 10 thread
5	1.7–1.9 mm	3	Size 10 thread
6	1.6–1.8 mm	3.5	Size 10 to 20 thread
7	1.5–1.65 mm	4	Size 10 to 20 thread
8	1.4–1.5 mm	4.5	Size 20 to 30 thread
9	1.25–1.4 mm	5	Size 30 thread
10	1.15–1.3 mm	5.5	Size 30 to 40 thread
11	1.05–1.1 mm	6	Size 40 to 50 thread
12	1 mm	6.5	Size 50 to 60 thread
13	0.85–0.95 mm	7	Size 70 to 80 thread
14	0.75–0.9 mm	7.5	Size 80 to 100 thread

Yarn and project

What size crochet hook should you use? Yarn weight and project guide

The hook on a yarn label is a starting point. Go smaller for tight fabric such as amigurumi, and larger for drape.

Find your yarn weight

Recommended crochet hook sizes by Craft Yarn Council yarn weight
Yarn weight	Also called	Craft Yarn Council hook range	Garments and squares	Amigurumi and baskets	Blankets and drape
#1 Super Fine	sock, fingering, baby	2.25–3.5 mm	2.25 mm (B-1)	2 mm	2.75 mm (C-2)
#2 Fine	sport, baby	3.5–4.5 mm	3.5 mm (E-4)	2.75 mm (C-2)	4 mm (G-6)
#3 Light	DK, light worsted	4.5–5.5 mm	4.5 mm (7)	3.5 mm (E-4)	5.5 mm (I-9)
#4 Medium	worsted, afghan, aran	5.5–6.5 mm	5.5 mm (I-9)	4 mm (G-6)	6.5 mm (K-10½)
#5 Bulky	chunky, craft, rug	6.5–9 mm	6.5 mm (K-10½)	5 mm (H-8)	8 mm (L-11)
#6 Super Bulky	super bulky, roving	9–15 mm	9 mm (M/N-13)	6.5 mm (K-10½)	11.5 mm (P-16)
#7 Jumbo	jumbo, roving	15–25+ mm	15 mm (P/Q)	9 mm (M/N-13)	19 mm (S)

Starting hooks from our recommender, for average tension. They are a place to begin a swatch, not a rule. Many worsted yarn labels suggest 5 mm, a little below the Craft Yarn Council range.

Getting started

Crochet hooks for beginners: the 3 hooks to start with

4.5 mmUS 7One size down
5 mmUS H-8Start here
5.5 mmUS I-9One size up

Why a 5 mm (H-8) hook and worsted yarn

A 5 mm hook with smooth, light-coloured worsted (#4) yarn is the easiest pair to learn with: the loops are big enough to see and count, and the yarn does not split easily. Add a 4.5 mm and a 5.5 mm hook later so you can adjust your gauge up or down one size. A cushioned or ergonomic handle helps if your hand tires.

Skip very fine steel hooks, jumbo hooks and dark, fuzzy or textured yarn until you can read your stitches.

Prefer the yarn, hook and pattern in one box? Our guide to complete crochet starter sets that include yarn and patterns explains which kits come with a hook.

Crochet hook, crochet needle and tapestry needle

Crochet hook: the tool with a hook at the tip that makes the stitches.
Crochet needle: another name many people use for a crochet hook. It means the same tool.
Tapestry or yarn needle: a blunt needle with a large eye, used to sew pieces together and weave in yarn ends. It does not make stitches.

Choosing a hook

Crochet hook anatomy, head styles and materials

Parts of a crochet hook

Point: pushes into the stitch. A sharper point gets into tight stitches; a blunter one splits fewer plies.
Throat and lip: the notch that catches the yarn when you yarn over.
Shaft: the straight part that sets the size of each loop. Its diameter is the hook size.
Thumb rest and handle: where you hold the hook. Their shape decides how comfortable it is over a long session.

Work your loops on the shaft, not the throat, or your stitches come out smaller than the hook size.

Inline and tapered hooks

Inline hooks have a head the same width as the shaft, with the throat cut straight into it. Susan Bates hooks are a well-known inline style. The deep throat holds the yarn securely, and many people find their loops come out very even.
Tapered hooks narrow at the throat and have a rounded head that sticks out a little. Boye hooks are a well-known tapered style. The head slides into stitches easily, and the yarn moves smoothly over it.

Neither is better. If your yarn keeps splitting or your stitches feel tight, try the other style in the same size.

Hook materials

Aluminium: smooth and fast, the most common choice for everyday yarn hooks.
Wood and bamboo: warm and slightly grippy, which helps with slippery yarn such as silk or some acrylics.
Steel: stiff and strong in the very small sizes used for thread and lace.
Plastic and resin: light, which is why many large and jumbo hooks are made from them.

If yarn drags on your hook, try a smoother material; if it slides off too easily, try a grippier one.

Comfort

Ergonomic crochet hooks, grip styles and specialty hooks

Knife grip and pencil grip

Knife grip: the hook lies under your palm, held like a knife. A longer handle stops the end pressing into your palm.
Pencil grip: the hook rests over your thumb and first finger, held like a pencil. A flat thumb rest helps you keep the hook turned the right way.

Both work. Hold the hook in the way that feels natural, then pick a handle that suits it.

Ergonomic hooks and hand comfort

A thicker or cushioned handle spreads your grip over a wider area, which many people with tired or sore hands find easier. A hook that is too small for your yarn also makes you work harder, so check your hook size before blaming your hands. Take regular breaks; the crochet session planner helps you pace longer projects.

This is general craft advice, not medical advice. If you have pain or a condition such as arthritis or carpal tunnel syndrome, ask a doctor or occupational therapist.

Tunisian, double-ended and specialty hooks

Tunisian hooks are longer, or have a cable, because Tunisian crochet holds many loops on the hook at once. Patterns usually use a larger hook than regular crochet in the same yarn, which helps stop the fabric curling. Read the Tunisian crochet hooks guide.
Double-ended hooks have a hook at each end, for working in the round or with two colours. See double-ended crochet hooks.
Croknit hooks have an eye at the end for a cord, so you can make knit-look fabric. See the Croknit hook guide.

Gauge

How hook size affects gauge, and how to measure an unlabeled hook

Crochet gauge calculator

Changing hook size to match gauge

Make a swatch of at least 4 in (10 cm) in the pattern's stitch, and block it the way you will block the finished piece.

More stitches than the pattern (fabric too small): change to a larger hook.
Fewer stitches than the pattern (fabric too big): change to a smaller hook.
Fabric stiff or board-like: try a larger hook, even if the stitch count is close.

Change one size at a time and swatch again. The crochet gauge calculator shows how far off you are, and the hook adjustment advisor suggests the next size to try.

Measuring an unlabeled or vintage hook

Measure the round shaft just below the throat, not the head or the handle. A hook and needle gauge with slots, or a caliper, gives a reliable reading. Then look up the millimetres in the chart above.

Old hooks often use UK sizes, where a bigger number means a smaller hook (UK 8 is 4 mm). Steel hooks use their own scale, so a steel size 10 is a fine thread hook, nowhere near a US J-10 (6 mm).

Crochet hook guides and reviews

Double-Ended Hooks
1 article
Hooks with a working end on each side, for crochet on the double and reversible fabric.
- Double-Ended Crochet Hooks: What They Are and How to Choose One
View all in Double-Ended Hooks
Croknit Hooks
1 article
Hooks made for the cro-knit technique.
- Croknit Hooks and Cro-Hooking: A Beginner's Guide
View all in Croknit Hooks
Tunisian Hooks
1 article
Long, cabled and double-ended hooks for Tunisian crochet.
- Tunisian Crochet Hooks: Types, Lengths and Sizes
View all in Tunisian Hooks
Hook Guides
1 article
Hook sizes, materials and how to choose the right hook.
- Crochet Hook Sizes Chart: US Letters and Millimetres
View all in Hook Guides

FAQ

Frequently asked questions about crochet hooks and sizes

Is there a US size A crochet hook?

No. The Craft Yarn Council chart starts at B-1 (2.25 mm). A 2 mm hook sits below it and is sometimes sold as A or 0, but it is sized in millimetres. The 4.5 mm hook has no letter at all; it is just called size 7.

What size is a G, H, I, J or K crochet hook in mm?

On the Craft Yarn Council chart, G-6 is 4 mm, H-8 is 5 mm, I-9 is 5.5 mm, J-10 is 6 mm and K-10½ is 6.5 mm. Some brands differ: Boye's G-6 is 4.25 mm and its I-9 is 5.25 mm. Always check the millimetres stamped on the hook.

Why do UK and steel hook numbers get smaller as the hook gets bigger?

Both scales come from old wire gauges, where a higher number meant thinner wire. So UK 14 is 2 mm and UK 0 is 8 mm, and steel size 14 is the finest thread hook. Metric millimetres avoid the confusion.

What does "double crochet hook" mean?

It can mean two things. A double-ended hook has a hook at each end, used for two-colour and Tunisian work. If you mean the hook for the double crochet stitch, there is no special one: use the size your yarn or pattern asks for, often 5 mm with worsted yarn.

What size crochet hook should a beginner buy?

A 5 mm (US H-8) hook with smooth, light-coloured worsted yarn. Add 4.5 mm and 5.5 mm hooks when you start following patterns, so you can go up or down a size to match the gauge.

Can I use a different hook size than the pattern says?

Yes, and you often should. The pattern's hook is a suggestion; what matters is matching the gauge. If your swatch has too many stitches, use a larger hook; too few, a smaller one.

Is a crochet needle the same as a crochet hook?

Yes. Crochet needle is another name for a crochet hook. It is different from a tapestry or yarn needle, which has an eye and is used to sew seams and weave in ends.

What hook should I use for amigurumi?

A hook smaller than the yarn label suggests, so the stitches are tight and the stuffing does not show. With worsted yarn many people use 3.5 to 4 mm. Use the recommender on this page as a starting point, then check a small swatch.