I hook in crochet refers to the 5.5mm hook size, one step up from the common H hook, useful when a pattern’s gauge runs slightly tight with an H or when working a marginally heavier yarn. I switch between the two sizes constantly depending on the specific skein. This guide covers when to reach for it.
When to Use an I Hook
Reach for an I hook if your gauge swatch with an H hook comes out too tight or dense, or if you are working a yarn slightly heavier than standard worsted weight. The looser stitches an I hook produces give more drape, useful for garments needing softer movement.
Frequently asked questions
Is an I hook bigger or smaller than an H hook?
An I hook is one size larger than an H hook, measuring 5.5mm compared to the H hook’s 5.0mm.
Want the exact millimeter measurement?
See the I hook’s size confirmed alongside common uses.
See the I hook size guide