Crochet Hook Size Converter
Convert common metric crochet hook sizes to US and UK labels and see a practical yarn-weight starting point.
Choose a metric size and click Convert.
Metric, US and UK crochet hook sizes
Metric millimeters are the clearest way to compare crochet hooks because letter and number systems vary by country and manufacturer. When a pattern gives a hook label without millimeters, verify the manufacturer’s conversion chart.
Hook size and yarn weight
Yarn weight suggestions are starting points only. Stitch pattern, desired drape, fiber and your personal tension can all change the best hook size. A gauge swatch is the most reliable check.