Using the Wraps per Inch (WPI) Gauge
To measure the thickness of your yarn, wrap approximately 1” of your yarn around a ruler or dowel and then match up the wraps with the gauge below. If you are measuring a very fine yarn, wrap and measure per 5 wraps. Wrap your yarn snugly but not tightly (do not stretch the yarn).
Note that “wraps per inch” is an approximate guide to yarn size and may vary widely, depending many factors including how tightly the yarn is wound, how much length is wound and how closely packed the yarn is. Also note that unfinished yarn will typically “bloom” when washed, effectively increasing the diameter of the yarn and decreasing the number of wraps per inch.
Using the Wraps per Inch (WPI) Reference Chart
This chart provides a rough target “wraps per inch” (WPI) for singles spun for the purpose of making plied yarns. These numbers come from a variety of sources, each with a different method of calculation. Your results may vary, depending on your spinning fibre. For the most consistent results, spin samples and finish your yarn, recording your WPI in unfinished singles, unfinished plied yarn, and also in your finished plied yarn. Use this chart as simply a starting point for your spinning.
For sure, you can download the PDF version of the WPI gauge above, but SweetGeorgia also designed a beautiful cherry wood spinning gauge that measures both twist and wraps per inch (1/2″ and 1″ notches) and it can be used as a weaver’s sett gauge or spinner’s yarn gauge. Check it out here »