Crochet Hook Size Chart

Find any crochet hook in US letters, metric millimeters, and old UK numbers, along with the yarn weight it is usually paired with. When in doubt, go by the millimeter size: it is the real diameter of the hook.

Metric (mm)US sizeOld UK / CanadaTypical yarn weight
2.25 mmB-113Super fine (1)
2.75 mmC-2—Super fine (1)
3.25 mmD-310Super fine (1)
3.5 mmE-49Super fine to fine (1–2)
3.75 mmF-5—Fine (2)
4 mmG-68Fine (2)
4.5 mm77Fine to light (2–3)
5 mmH-86Light (3)
5.5 mmI-95Light to medium (3–4)
6 mmJ-104Medium (4)
6.5 mmK-10½3Medium to bulky (4–5)
8 mmL-110Bulky (5)
9 mmM/N-1300Bulky to super bulky (5–6)
10 mmN/P-15000Super bulky (6)
15 mmP/Q—Super bulky to jumbo (6–7)
16 mmQ—Jumbo (7)
19 mmS—Jumbo (7)

Steel hooks for thread crochet (0.6–2.1 mm) use their own numbering, where larger numbers are smaller hooks.

How to choose a crochet hook size

  1. Check the yarn label. Most labels print a recommended hook size and a gauge.
  2. Follow the pattern if it lists a hook, since the designer's gauge depends on it.
  3. Make a gauge swatch. Too many stitches per 4 inches means go up a hook size; too few means go down.
  4. Go bigger for drape (shawls, garments) and smaller for dense fabric (amigurumi, baskets).

How to measure an unmarked hook

Push the shaft of the hook, just below the throat, through the holes of a needle and hook gauge. The smallest hole it fits through snugly is its size. Without a gauge, measure the shaft diameter with calipers in millimeters and look it up in the chart above.

Crochet hook size FAQ

What size crochet hook is the most common?

The 5 mm (H-8) hook is the most common all-purpose size. It pairs with light and worsted weight yarn, which most beginner patterns call for.

Is the millimeter size or the letter more accurate?

The millimeter size. Letters can differ slightly between brands (a G hook may be 4 mm or 4.25 mm), but the millimeter measurement is the actual shaft diameter.

How do I convert UK crochet hook sizes?

Old UK hook numbers run backwards: higher numbers are smaller hooks. A UK 8 is 4 mm (US G-6) and a UK 6 is 5 mm (US H-8). Modern UK patterns usually list millimeters.

What hook should I use for worsted weight yarn?

Worsted is a medium (4) weight yarn. The Craft Yarn Council recommends 5.5–6.5 mm hooks (I-9 to K-10½), although many patterns use a 5 mm H-8 for tighter fabric.

Matching yarn to your hook? See the yarn weight chart, or turn a picture into a chart with the crochet pattern generator.