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Crochet hook size converter

Pick a hook in millimeters or by US letter to see the other, or use the full chart below.

Your result

Same hook5 mmUS H-8
Crochet hook size chart: metric and US
MetricUS
2.25 mmB-1
2.75 mmC-2
3.25 mmD-3
3.5 mmE-4
3.75 mmF-5
4 mmG-6
4.5 mm7
5 mmH-8
5.5 mmI-9
6 mmJ-10
6.5 mmK-10½
8 mmL-11
9 mmM/N-13
10 mmN/P-15
11.5 mmP-16
15 mmP/Q
16 mmQ
19 mmS
25 mmT/U/X
30 mmT/X

Craft Yarn Council sizes. The UK and Europe size hooks in millimeters.

Crochet hook size chart: metric mm and US letter sizes
Crochet hook size chart: metric mm and US letter sizes. Free to print and save.

How to use it

  1. Pick the hook size from your pattern, in millimeters or by US letter.
  2. Read the same hook in the other system.
  3. Check your gauge: hooks of the same size from different makers can work up differently.

Questions

What size is an H hook in mm?

An H-8 hook is 5 mm. G-6 is 4 mm, I-9 is 5.5 mm and J-10 is 6 mm.

Which hook size is most common?

For worsted weight yarn, an H-8 (5 mm) to I-9 (5.5 mm) hook is the usual choice.

Why are some letters shared, like M/N?

Some makers label the same millimeter size with different letters, so the chart shows both. The millimeter size is the one to trust.

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