Changing yarn weight or needle size can have a significant impact on the finished project, so standardized systems have been spread about, as well as conversion systems for regional standards (especially needle sizes). Yarn weight is important in achieving the correct
gauge or tension for a particular project and can help with yarn substitution. The
Craft Yarn Council of America has developed a system that seeks to standardize the labeled weights of yarn. Most yarns state their weight on the ball band but some may not, only giving the composition. Some brands use a standardized numbering system that uses seven ranges of relative thickness of
yarn. However there are methods for individuals to gauge weight for themselves. ==Wrap method==