How to Measure Handspun Using Wraps Per Inch (WPI)

Wraps per inch is just one of the measurements I take when I’m planning a project. It can be a useful way to compare your handspun to commercial yarns or just see whether you’re on track to spin the kind of yarn you want.

But it can be a confusing measurement which has its pitfalls because different people measure it in different ways. I discuss those pitfalls and many other useful tips in my WPI video below, but here are the two ways I measure wraps per inch.

Wrapping Method

Wrap your yarn around a solid object like a ruler, or a piece of dowel. Make sure to roll your yarn on from the side of the object rather than the end to avoid adding or removing twist.

Lay the wraps of yarn next to each other so there are no gaps in between but without squeezing them in tightly or overlapping.

When you’ve wrapped one inch or more, count the number of wraps in one inch. That number is your wraps per inch. The photo above shows 11 wraps per inch (WPI). Although there are 12 wraps in total, only 11 fit between the inch markings on the ruler.

For accuracy when measuring thicker or less-consistent yarns, wrap 2 or more inches, then divide the number of wraps by the number of inches.

And for speed when measuring very fine yarns, count the number of wraps in half (or a quarter of) an inch and multiply by 2 (or 4).

Yarn Gauge Method

For a quick reference to check my yarn while I’m spinning, I use a yarn gauge. They’re also known as spinner’s gauges or spinner’s control cards. They have a series of lines of different heights, labelled with the number of wraps per inch that line equates to.

To us a yarn gauge, take an average section of your yarn and lay it over the gauge. Compare it to each line until you find one it fits over perfectly. I look for one where the only part of the line visible is in the valley between the ply bumps — the rest of the line is hidden under the yarn.

You can also use them to measure singles while you’re spinning, in which case look for a line that’s completely covered by the yarn.

If you find it tricky to judge the size, try holding the gauge perpendicular to the yarn (don’t press down on the yarn) and look for a line that’s the same size.