Crochet Hook Size Conversion Chart

Convert crochet hook sizes between US letter designations, metric millimeters, and UK/Canadian numbers. Match every hook size to the correct yarn weight category.

Select US Hook Letter:

Craft Standards Conversion

Size H-8 (5mm) Hook

Metric: 5 mmUK / Old: No. 6

🧶 Recommended Yarn Weight:

Worsted / Aran (Medium #4)

🧣 Ideal Projects:

Worldwide most popular hook size. Afghan throw blankets, cozy winter scarves, tote bags.

🧵 Gauge Swatch Pro-Tip:If your crocheted piece is curling or stiff like cardboard, your tension is too tight — size UP by 0.5mm (e.g. from G-6 4mm to H-8 5mm). If your stitches are floppy with loose see-through gaps, size DOWN by 0.5mm!