The term “wraps per inch” refers to the number of times the yarn must be wrapped around an inch gauge to cover one inch (2.5 cm) of space. Taking the time to stop spinning for a quick check of the WPI count helps the spinner to keep control of the grist of the yarn being spun and helps ensure that all yarns for a project are spun to the same grist.

There are three ways to wrap yarn around the gauge tool:

1. Pack in as much yarn into the space as possible, pushing each wrapping tight up against its neighbor but not so tightly that the wraps overlap each other.

2. Wrap the yarn so that each wrapping gently snuggles up to its neighbor until the space is filled.

3. Wrap the yarn so there is space to lay another strand of yarn between the two neighboring wraps.

It does not matter which wrapping method you use as long as you use the same wrapping method consistently. My personal preference is method #2 - each strand touching the neighboring strand but not densely packed in.

Wrapping gauges are available in a wide variety of materials with prices ranging to match the materials and craftsmanship. Some will give a one inch (2.5 cm) measure only, others will feature a variety of different sized gauges. WPI tools featuring both one inch (2.5 cm) and two inch (5 cm) are common. Some will have even more capabilities. My favorite is one made by a friend that features four different gauges all in one small tool.

WPI gauges also come in a variety of shapes. Look for a round one as they are the easiest to wrap.

Using a wrap gauge will alter the twist of the yarn to a small degree. To keep this to the absolute minimum wrap the yarn onto the gauge by turning the gauge towards the wheel, letting the turning of the tool pull the yarn from the bobbin through the orifice as you wind.

The individual wraps may be counted as they are wrapped or after the entire space has been wrapped. For the most accurate WPI count, wrap several inches and then divide the total number of wraps by the total number of inches to get the WPI.

To make a inch gauge, all you need is a pencil, a ruler, and some type of permanent maker to mark off segments on the pencil. Carefully measure out the differing lengths you want on your gauge and mark them on your pencil. Mark all the way around so the marks are always visible as you wrap your yarn.