Crochet hook size guide

2 mm crochet hook (Steel 4 (not a regular-hook letter size))

2 mm is the metric diameter. The Craft Yarn Council pairs it with steel 4 (not a regular-hook letter size). Use the millimeter marking when labels disagree.

Immediate answer

2 mm → Steel 4 (not a regular-hook letter size)

Diameter
2 mm
CYC US label
Steel 4 (not a regular-hook letter size)

Relative diameter visualization—not a physical on-screen ruler.

CYC starting range

Often paired with a category shown on the yarn label

  • Check the pattern gauge first.
  • Make and measure a gauge swatch.
  • Change tool size if the swatch misses gauge.

How to use this size

Treat the label as a starting point.

  1. 1. Read the pattern. Note the stated tool, yarn, stitch pattern, and target gauge.
  2. 2. Match millimeters. If a letter or number conflicts, use 2 mm.
  3. 3. Swatch and wash. Measure the fabric the same way the finished project will be treated.
  4. 4. Adjust one step. Use a smaller tool for more stitches per inch or a larger one for fewer.

Source notes

Last reviewed September 1, 2026