Patterns from different countries name hook sizes differently. Choose a size in millimetres, US or UK terms and this converter shows the matching sizes, plus the yarn weights that hook is usually paired with.
Metric-
US-
UK / Canada-
Usually used with: -
| Metric | US | UK / Canada |
|---|
Why are there three systems?
Metric sizes give the actual diameter of the hook shaft in millimetres, which is why most modern patterns use them. US sizes use letters and numbers, and older UK and Canadian patterns use a numbering system that runs the other way: the bigger the number, the smaller the hook.
Which hook for which yarn?
The suggested ranges follow the standard yarn weight system used on most yarn labels. They are a starting point. Use a smaller hook for firm fabric such as amigurumi, and a larger one for drapey shawls and blankets.