Crochet Pattern Terms Differences Between British and American English
A chart for translating crochet patterns written in British English crochet terms into American English crochet terms.

Hook Size To Use With Thread Size
At About Crochet: This chart can be helpful in deciding upon a hook size to use with a certain size of crochet thread.

Converting Patterns Between Knit and Crochet
Easy and Cheap Crafts site: Tips to help you when converting a pattern between crocheting and knitting.

Hook Conversion Chart
At Yarn Forward: Metric sizes (mm) vs US vs UK.

Hook Conversion Chart - Steel Hooks
At Yarn Forward: Converting metric sizes (mm) vs US vs UK.

International Crochet Symbols - Converting Between US/Japan and Europe
At Hass Designs: The differences shown between US/Japan pattern symbols and European symbols with the same meaning.