How to use the crochet hook size chart
Find the size your pattern asks for in any column and read across. If a pattern gives a letter and your hook only shows millimeters, or the other way round, the converter above does the lookup for you. Most hooks have the size stamped on the flat thumb rest. The Craft Yarn Council hooks and needles standard lists the same metric and US sizes.
Choosing a hook for your yarn
Your yarn label usually suggests a hook size. Use it as a starting point, crochet a swatch and measure it. If you get too many stitches per 4 inches, go up a hook size; if you get too few, go down. Our yarn weight chart lists the usual hook range for each weight.
One step up is a bigger change than it looks. In the everyday range from 3.5 to 6.5 mm, each hook is 7 to 13 percent wider than the one before it. Going from an H-8 (5 mm) to an I-9 (5.5 mm) adds 10 percent to the shaft. Crochet Penguin sums up the result: a bigger hook gives a larger gauge and a bigger finished piece, and a smaller hook gives tighter stitches. The gauge guide shows how to check your swatch.
Crochet hook sizes for each yarn weight
The Craft Yarn Council's yarn weight system suggests a hook range for each of its eight weights. These are the ranges it gives, from lace to jumbo.
| Yarn weight | Hook (mm) | Hook (US) |
|---|---|---|
| 0 Lace | Steel 1.4 to 2.25 | Steel 6, 7, 8 or B-1 |
| 1 Super fine | 2.25 to 3.5 | B-1 to E-4 |
| 2 Fine | 3.5 to 4.5 | E-4 to 7 |
| 3 Light | 4.5 to 5.5 | 7 to I-9 |
| 4 Medium | 5.5 to 6.5 | I-9 to K-10½ |
| 5 Bulky | 6.5 to 9 | K-10½ to M-13 |
| 6 Super bulky | 9 to 15 | M-13 to Q |
| 7 Jumbo | 15 and larger | Q and larger |
Lace weight and crochet thread use steel hooks, which have their own sizes below.
How crochet hook sizes are measured
A hook's size is the width of its shaft, the straight part between the head and the thumb rest. Sarah Maker and Crochet Penguin both define it this way. The millimeter number is that width, so it means the same thing on every brand. Letters and numbers are labels, and brands don't always agree on them. Crochet Penguin points out that Boye labels its G hook 4.25 mm, while the standard G-6 is 4 mm.
If a hook has lost its markings, Sarah Maker suggests a hook gauge. It is a small card with holes labeled by size. Push the shaft through the smallest hole it fits, and read the size.
In-between and jumbo hook sizes
The Craft Yarn Council's list has a few sizes the main table leaves out. Some fall between the main sizes, and some are jumbo hooks for very thick yarn.
| Metric | US |
|---|---|
| 2.5 mm | none |
| 3.125 mm | D |
| 4.25 mm | G |
| 5.25 mm | I |
| 5.75 mm | J |
| 7 mm | none |
| 11.5 mm | P-16 |
| 12 mm | none |
| 16 mm | Q |
| 25 mm | T/U/X |
| 30 mm | T/X |
A pattern that calls for a plain G, I or J hook may mean one of these in-between sizes. Check the millimeter size in the pattern notes.
Steel crochet hook sizes for thread
Steel hooks are for crochet thread and fine lace. Their numbers run backward: the Craft Yarn Council notes that a higher number means a smaller hook, the reverse of regular hooks. This table follows Sarah Maker's steel hook chart.
| Metric | US steel | UK |
|---|---|---|
| 3.5 mm | 00 | none |
| 3.25 mm | 0 | 0 |
| 2.75 mm | 1 | 1 |
| 2.25 mm | 2 | 1½ |
| 2.1 mm | 3 | 2 |
| 2 mm | 4 | 2½ |
| 1.9 mm | 5 | 3 |
| 1.8 mm | 6 | 3½ |
| 1.65 mm | 7 | 4 |
| 1.5 mm | 8 | 4½ |
| 1.4 mm | 9 | 5 |
| 1.3 mm | 10 | 5½ |
| 1.1 mm | 11 | 6 |
| 1 mm | 12 | 6½ |
| 0.85 mm | 13 | 7 |
| 0.75 mm | 14 | none |
Steel numbers are not consistent between brands. The Craft Yarn Council's steel chart lists two separate number series, so the same number can mean two sizes. Match on millimeters here too. It also says the most common crochet threads are sizes 3, 5, 10, 20 and 30, and that size 100 is the finest.
Crochet hooks and knitting needles
Hooks and needles share the same metric sizes, and in this chart the US numbers line up too. Of the 14 hooks in the main table that carry a number and have a knitting needle at the same millimeter size, 14 share the needle's US number. An H-8 hook and a US 8 needle are both 5 mm. The knitting needle size chart has the full needle list.
Hook shapes and materials
Hooks come in two head shapes. On an inline hook, the head lines up with the shaft. On a tapered hook, the throat curves in slightly just below the head, as Joy of Motion Crochet describes it. Yarn.com's buying guide says beginners may find inline hooks easier for keeping stitches even.
Yarn.com also compares materials. Wood and bamboo grip the yarn, which helps with slippery fibers. Aluminum is light and slides easily through wool and other fibers that stick. Steel is the strongest and is used for the smallest sizes. Tunisian (afghan) hooks are longer, because the stitches stay on the hook during the forward pass.
Sources
- Craft Yarn Council: hooks and needles (metric and US sizes, including the in-between and jumbo sizes)
- Craft Yarn Council: steel crochet hook and thread sizes
- Craft Yarn Council: standard yarn weight system (hook range by weight)
- Sarah Maker: crochet hook sizes and comparison chart (steel sizes, measuring a hook)
- Crochet Penguin: crochet hook sizes (brand differences, common sizes)
- Yarn.com: crochet hook buying guide (shapes, materials, Tunisian hooks)
- Joy of Motion Crochet: crochet hooks and hook sizes (inline and tapered heads)