http://www.karpstyles.com/crochet/hook-chart.htmlCrochet Hook comparison chart.Crochet hook sizes differ depending on country, the brand of hook
and even can depend on the age of the pattern.
Our large selection of Crochet Hooks to purchase can be found in our
Catalog Crochet Hook Conversion Chart | Metric | USA | UK | 2.00 mm | - | 14 | 2.25 mm | 1 / B | 13 | 2.50 mm | - | 12 | 2.75 mm | C | 11 | 3.00 mm | - | 11 | 3.25 mm | D | 10 | 3.50 mm | 4 / E | 9 | 3.75 mm | F | - | 4.00 mm | 6 | 8 | 4.25 mm | G | - | 4.50 mm | 7 | 7 | 5.00 mm | 8 / H | 6 | 5.50 mm | 9 / I | 5 | 6.00 mm | 10 / J | 4 | 6.50 mm | 10 1/2 / K | 3 | 7.00 mm | - | 2 | 8.00 mm | - | 0 | 9.00 mm | 15 / N | 00 | 10.00 mm | P | 000 | 15.75 mm or 16mm | Q | - | | Steel Hook Chart (thread hooks) | Metric | USA | UK | .6 mm | 14 | 6 | .75 mm | 13 | - | .70 mm | 12 | 5 | .8 mm | 11 | - | 1 mm | 10 | 4 | 1.15 mm | 9 | - | 1.25 mm | 8 | 3 | 1.50 mm | 7 | 2.5 | 1.6 mm | 6 | - | 1.7 mm | 5 | - | 1.75 mm | 4 | 2 | 1.85 mm | 3 | - | 1.95 mm | 2 | - | 2 mm | 1 | 1 | 2.25 mm | 0 | 00 | 3 mm | 00 | - | |