Crochet Hook Guide

Crochet Hook Guide

Crochet hook sizes are labeled with a US letter or number and a millimeter size, and the mm size is the one to trust. Common conversions: F/5 = 3.75 mm, G/6 = 4.0 mm, 7 = 4.5 mm, H/8 = 5.0 mm, I/9 = 5.5 mm, J/10 = 6.0 mm, K/10.5 = 6.5 mm.

Regardless of hook size, you should always complete a gauge swatch using the hook that you intend to use in your project and compare it to the pattern gauge information. If your swatch gauge is larger than the pattern gauge, redo a swatch using a smaller hook. Conversely, if your swatch gauge is too small then redo the swatch using a larger hook to obtain the gauge indicated in the pattern.

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Regular Crochet Hook Sizes

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

Source: www.yarnstandards.com

Steel Crochet Hook Sizes

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

Source: www.yarnstandards.com

Frequently asked questions

What are the standard crochet hook sizes?

Standard crochet hooks run from size B-1 (2.25 mm) up to T/X (30 mm). Steel hooks, used for thread and fine lace, are numbered separately and run from size 12 (0.6 mm) to size 00 (3.5 mm). Hook makers label sizes with a US letter, a US number and a metric size in millimeters. The millimeter size is the most reliable, because letters and numbers vary between brands. The chart on this page shows every size side by side.

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

A US G-6 hook is 4.0 mm, an H-8 is 5.0 mm, an I-9 is 5.5 mm and a J-10 is 6.0 mm. For the sizes around them, an F-5 is 3.75 mm and a K-10.5 is 6.5 mm. Always check the millimeter size printed on your hook, because it is the number your pattern is most likely to use.

What size is a US number crochet hook, like size 7 or size 10, in mm?

In US regular hooks, size 7 is 4.5 mm, size 8 (H) is 5.0 mm, size 9 (I) is 5.5 mm and size 10 (J) is 6.0 mm. Going lower, size 4 (E) is 3.5 mm, size 5 (F) is 3.75 mm and size 6 (G) is 4.0 mm. Steel hooks also have numbers, but they follow a separate scale, so a steel size 10 is a much smaller hook than a regular size 10.

What crochet hook letter or number matches my millimeter size?

Common matches: 4.0 mm is G-6, 5.0 mm is H-8, 5.5 mm is I-9 and 6.0 mm is J-10. Some sizes in between, such as 4.5 mm, have a number (size 7) but no letter. The chart on this page lists every size. If your swatch comes out larger than the pattern's gauge, use a smaller hook. If it comes out smaller, use a larger hook.

What are steel crochet hook sizes?

Steel crochet hooks are the small hooks used for fine thread work such as lace and doilies. They are numbered from 12 (0.6 mm, the smallest) to 00 (3.5 mm, the largest), and the higher the number, the smaller the hook. This is the opposite of regular hooks, where a bigger number means a bigger hook.