What Size Hook for Worsted Weight Yarn?

I-9 to K-10.5 (5.5-6.5mm) is the published range for worsted weight in crochet — noticeably larger hooks than the equivalent knitting needle range, since crochet fabric at a given yarn weight is typically worked at a looser gauge than knitting is.

Why crochet's range sits at bigger sizes than knitting's

At the identical yarn weight, crochet stitches naturally take up more physical space per stitch than knit stitches do, which is part of why the standard hook range for worsted weight runs larger than the standard needle range for the same yarn — this isn't a stitch-for-stitch equivalent scale, and comparing hook and needle sizes directly by number doesn't tell you much about matching gauge between the two crafts.

Swatching within the range

J-10 (6mm) is a reasonable middle starting point — swatch there first, then size down for a tighter, denser fabric or up for a looser, drapier one, adjusting based on your own gauge rather than assuming the middle size is automatically correct.

Amigurumi breaks this range on purpose

Amigurumi deliberately uses a hook sized well below this standard range — often several sizes smaller than even I-9 — specifically to produce a tight, dense fabric that keeps stuffing from showing through. See what hook size for amigurumi for the specific reasoning; the standard worsted-weight range above assumes a normal, drapey fabric is the goal, which amigurumi explicitly isn't.

FAQ

Does hook material (aluminum, wood, plastic) affect what size actually produces a given gauge? Not the labeled size itself, but grip and glide can subtly affect an individual crocheter's tension — if your gauge seems consistently off from what a given hook size should produce, the hook's surface material is worth considering alongside the size itself.

Is there a single "correct" hook size for worsted weight, or does it always depend on the project? It depends on the project's intended fabric — a garment wanting drape, a firm bag wanting structure, and amigurumi wanting density all reasonably use different hook sizes at the identical yarn weight, since "correct" here means "correct for the intended result," not one fixed number.

Does a bigger hook always mean using less yarn for the same project? Generally yes, since a bigger hook produces fewer, larger stitches to cover the same area — but the exact relationship depends on stitch pattern too; check the Yarn Quantity Estimator for your specific combination rather than assuming a fixed ratio.