Yarns are measured by the density of the yarn, which is described by various units of textile measurement relating to a standardized length per weight. These units do not directly correspond to thread diameter.
The most common weight system specifies the length of the thread in kilometres required to weigh 1 kilogram. Therefore, a greater weight number (indicated in the American standard by the abbreviation wt) indicates a thinner, finer thread. The American standard of thread weight was adopted from the Gunze Count standard of Japan which uses two numbers separated by a forward slash. The first number corresponds to the wt number of the thread and the second number indicates how many strands of fiber were used to compose the finished thread. It is common to wrap three strands of the same weight to make one thread, though this is not a formal requirement in the US standard (which is therefore less informative).
|Weight||Gunze Count||Common Use|
|Light||60 wt||#60/3||bobbin or appliqué|
|Thin||50 wt||#50/3||bobbin or appliqué|